Magneto-resistance effect element, magneto-resistance effect head, magneto-resistance transducer system, and magnetic storage system

ABSTRACT

A magneto-resistance effect element is adapted that a non-magnetic layer (9, 18), a free layer (3 b , 19), another non-magnetic layer (4, 25), a fixed layer (5, 26), and a fixing layer (6 b , 27) are formed vertically symmetric with respect to a first magnetic layer (8 b ), to which a vertical bias magnetic field is applied from an underlying layer (2 a ) for a vertical bias layer (2 b ). The magneto-resistance effect element operates in CPP mode. Generally, the free layer is unavoidably subjected to the influence of a circular electric magnetic field caused by a current flowing perpendicularly to the film surface. However, in the magneto-resistance effect element, the influence of the electric magnetic field to which the free layer (3 b ) is subjected is opposite to that of the electric magnetic field to which the second free layer (19) is subjected, thereby canceling out the influences as a hole.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of patent application Ser. No. 11/227,143filed Sep. 16, 2005 now U.S. Pat. No. 7,158,355, which is a divisionalapplication of Ser. No. 10/803,144 filed Mar. 18, 2004, now U.S. Pat.No. 6,999,287 issued Feb. 14, 2006, which in turn is a divisionalapplication of Ser. No. 10/442,209, filed May 21, 2003, now U.S. Pat.No. 6,747,853 issued Jun. 8, 2004, which is a divisional application ofSer. No. 09/916,529 filed Jul. 30, 2001, now U.S. Pat. No. 6,934,132issued Aug. 23, 2005, the complete contents of which is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a magneto-resistance effect element forwriting and reading an information signal on magnetic storage media, amagneto-resistance effect head comprising the magneto-resistance effectelement, a magneto-resistance transducer system comprising themagneto-resistance effect head, and a magnetic storage system comprisingthe magneto-resistance transducer system. More particularly, the presentinvention relates to a magneto-resistance effect element that reducesnoise in a read signal.

2. Description of the Related Art

Conventionally disclosed is a magnetic read transducer that is referredto as a magneto-resistance sensor (hereinafter referred to as an MRsensor) or a head. This magnetic read transducer can read data from amagnetic surface at high linear densities. The MR sensor allows the readelement to vary the electrical resistance as the function of thestrength and the orientation of a magnetic flux applied from the outsidein order to measure a variation in electrical resistance, therebydetecting a magnetic signal.

Such a conventional MR sensor operates based on the anisotropicmagneto-resistance effect (hereinafter referred to as an AMR effect). Bythis effect, the component of a change in electrical resistance of theread element varies in proportion to the second power of the cosine ofthe angle between the orientation of magnetization and the direction ofthe sense current flowing through the read element. The AMR effect isdescribed in more detail in an article entitled “Memory, Storage, andRelated Applications”, D. A. Thompson, IEEE Transactions on Magnetics,Vol. MAG-11, No. 4, pp. 1039 (1975).

In addition, disclosed lately is a more prominent magneto-resistanceeffect by which a change in electrical resistance of the layeredmagnetic sensor is caused by spin-dependent transportation of conductionelectrons between magnetic layers via a non-magnetic layer andspin-dependent scattering associated therewith at layer boundaries. Thismagneto-resistance effect is identified by various names such as the“giant magneto-resistance effect” or the “spin valve effect”. Such amagneto-resistance sensor is formed of suitable materials to provideimproved detection sensitivity and greater changes in electricalresistance in comparison with a sensor which makes use of the AMReffect. In a MR sensor of this type, in-plane resistance between a pairof ferromagnetic layers separated by a non-magnetic layer varies inproportion to the cosine of the angle between the orientations ofmagnetization of the aforementioned pair of ferromagnetic layers. InJapanese Patent Laid-Open Publication No. Hei 2-61572 submitted in July1988, for claiming priority, described is a layered magnetic structurefor providing a significant change in MR caused by an anti-parallelalignment of the orientations of magnetization in the magnetic layers.

On the other hand, such a phenomenon has been recently discovered inwhich a relative change in orientation of magnetization of ferromagneticbodies disposed above and below a very thin insulation layer (barrierlayer) through which a tunneling current flows, causes a change inelectrical resistance. And, the layered structure made up of theferromagnetic layer, the barrier layer, and the ferromagnetic layer istermed a ferromagnetic tunnel junction. For example, ferromagnetictunnel junctions are introduced in “Journal of Applied Physics”, Vol. 79(8), No. 15, pp. 4724 (1996).

On the other hand, in a shield type element that makes use of aferromagnetic tunnel junction, it is necessary to conduct a sensecurrent for detecting a change in electrical resistance of the elementin perpendicular relation to the tunnel junction. However, the structuresimilar to the shield type element employing the conventional spin valvepresents a problem that the sense current flows through a vertical biaslayer for controlling the magnetic domain of the free layer disposednear the tunnel junction to reduce the current flowing through thetunnel junction, thereby providing a reduced change in electricalresistance.

In order to overcome this problem, a read head was disclosed in JapanesePatent Laid-Open Publication No.Hei 10-162327 submitted on Nov. 27,1996, for claiming priority. The read head, employing a ferromagnetictunnel junction film, has a structure in which the vertical bias layeris not in contact with the free layer.

FIG. 1 is a fragmentary sectional view illustrating the prior-artferromagnetic tunnel head described in Japanese Patent Laid-OpenPublication No. Hei 10-162327. FIG. 1 illustrates the structure of apatterned ferromagnetic tunnel junction element, or a magneto-resistanceeffect element 30, having an insulation layer 11 disposed between avertical bias layer 2 b and a free layer 3 b. This structure can preventa sense current from flowing through the vertical bias layer 2 b.

However, since the insulation layer 11 disposed between the verticalbias layer 2 b and the free layer 3 b acts also as a magnetic separationlayer, it is difficult in the magneto-resistance effect element 30 toapply a vertical bias magnetic field of a sufficient magnitude to thefree layer 3 b. This presents such a problem that the magnetic domain ofthe free layer 3 b is controlled insufficiently to cause the hysteresisof the R-H loop to increase for the shield type sensor, therebyproviding a high-noise-level read signal upon reading magneticinformation on a storage medium.

In order to overcome this problem, a read head was disclosed in JapanesePatent Laid-Open Publication No. Hei 10-255231 submitted on Mar. 7,1997, 1996, for claiming priority. The read head, employing aferromagnetic tunnel junction film, has a structure in which thevertical bias layer is in contact with the free layer.

FIGS. 2 and 3 are fragmentary sectional views of the ferromagnetictunnel head described in Japanese Patent Laid-Open Publication No. Hei10-255231. FIGS. 2 and 3 illustrate the structure of a layered bodycomprising the free layer 3 b, the non-magnetic layer 4, and the fixedlayer 5, in which the vertical bias layer 2 b is in direct contact withthe end portion of either the free layer 3 b or the fixed layer 5.

However, the structure shown in FIGS. 2 and 3 presents the followingproblem. As will be described in the preferred embodiments of thepresent invention, the read head, which was actually fabricated to thestructure shown in FIGS. 2 and 3, caused the sense current to flow intothe vertical bias layer 2 b and thus insufficiently flow through thenon-magnetic layer 4. It is thereby made impossible to providesufficient output of the sense current. The low output made itimpossible to provide sufficient (S/N) ratios and bit error rates. Asdescribed above, this structure may make it possible in principle toprevent the sense current from flowing through the vertical bias layer 2b and thereby bypassing the non-magnetic layer 4. However, the verticalbias layer 2 b is disposed in close proximity to the end portion of thenon-magnetic layer 4 in the layered body made up of the free layer 3 b,the non-magnetic layer 4, and the fixed layer 5. Thus, it is difficultto fabricate this structure precisely enough to prevent the sensecurrent from flowing through the vertical bias layer 2 b and therebybypassing the non-magnetic layer 4.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a magneto-resistanceeffect element, a magneto-resistance effect head, a magneto-resistancetransducer system, and a magnetic storage system, which can prevent thesense current from flowing into the vertical bias layer, provide a readsignal of a low noise level, and a good (S/N) ratio and bit error rate.

A magneto-resistance effect element according to the present inventioncomprises a lower conductive layer and a free layer provided on thelower conductive layer and having an orientation of magnetization variedby a magnetic field applied thereto. The magneto-resistance effectelement also comprises a non-magnetic layer provided on top of the freelayer, a fixed layer provided on the non-magnetic layer and having apinned orientation of magnetization, and a vertical bias layer, providedon the lower conductive layer, for applying a magnetic field to the freelayer. The magneto-resistance effect element is adapted that the freelayer is greater in length in the direction of a magnetic field appliedthereto by the vertical bias layer than the fixed layer, and a sensecurrent for detecting a change in electrical resistance of thenon-magnetic layer flows substantially in perpendicular relation to thenon-magnetic layer.

In the present invention, the free layer is made greater in length thanthe fixed layer in the direction of magnetic field applied by thevertical bias layer, thereby allowing only the free layer to be disposednear the vertical bias layer. This allows the vertical bias layer toeffectively apply a vertical bias magnetic field to the free layer andmakes it possible to prevent the leakage of a sense current from thefixed layer to the vertical bias layer. This allows almost all the sensecurrent, which is applied to the magneto-resistance effect element todetect a change in electrical resistance, to flow through thenon-magnetic layer, thereby making it possible to reduce noise in theread signal waveform and improve the (S/N) ratio and bit error rate.Incidentally, that the sense current flows substantially inperpendicular relation to the aforementioned non-magnetic layer meansthat the sense current flows in orthogonal relation thereto to such anextent as to measure a change in electrical resistance of thenon-magnetic layer without any trouble. In addition, the direction ofthe magnetic field applied by the aforementioned vertical bias layeragrees with the direction perpendicular to the direction in which theaforementioned sense current flows on a plane parallel to an air bearingsurface of the magneto-resistance effect head.

In addition, it is preferable that the lower conductive layer has arecessed portion, and at least part of the vertical bias layer is buriedin the recessed portion.

This makes it possible to place the vertical bias layer and the freelayer to be flush with each other, and allows the vertical bias layer toapply a vertical bias magnetic field smoothly and effectively to thefree layer.

Furthermore, at least part of the free layer can be brought into directcontact with the vertical bias layer. Alternatively, the underlyinglayer for free layer may be provided below the free layer such that theunderlying layer for free layer is brought into contact with thevertical bias layer. A vertical bias layer protective layer may beprovided on the vertical bias layer such that the vertical bias layerprotective layer is brought into contact with the free layer or theunderlying layer for free layer.

This allows the vertical bias layer to apply a vertical bias magneticfield more positively and effectively to the free layer.

A magneto-resistance effect element according to the present inventioncomprises a lower conductive layer, a magnetic layer provided on thelower conductive layer, and a free layer provided on the magnetic layerand having an orientation of magnetization varied by a magnetic fieldcoupled magnetically to the magnetic layer and applied thereto. Themagneto-resistance effect element also comprises a non-magnetic layerprovided on the free layer, a fixed layer provided on the non-magneticlayer and having a pinned orientation of magnetization, and a verticalbias layer, provided on the lower conductive layer, for applying amagnetic field to the free layer. The magneto-resistance effect elementis adapted that the magnetic layer is greater in length in the directionof a magnetic field applied thereto by the vertical bias layer than thefree layer, and a sense current for detecting a change in electricalresistance of the non-magnetic body flows substantially in perpendicularrelation to the non-magnetic layer.

In addition, the magnetic layer can be magnetically coupled to the freelayer by anti-ferromagnetic coupling or ferromagnetic coupling.Furthermore, a second non-magnetic layer may be provided between themagnetic layer and the free layer.

In the present invention, a vertical bias magnetic field is once appliedto the magnetic layer from the vertical bias layer, and then thevertical bias magnetic field is applied to the free layer from themagnetic layer. The vertical bias magnetic field is thus applied to thefree layer through the two steps, thereby facilitating the control ofthe vertical bias magnetic field applied to the free layer. In addition,in the direction of the magnetic field applied by the vertical biaslayer, the free layer is made greater in length than the free layer,thereby placing only the magnetic layer near the vertical bias layer.This allows the vertical bias layer to effectively apply the verticalbias magnetic field to the magnetic layer and makes it possible toprevent the leakage of sense current from the layered body to thevertical bias layer, thereby allowing almost all sense current toconduct through the non-magnetic layer.

Furthermore, at least part of the magnetic layer can be brought intodirect contact with the vertical bias layer. Alternatively, theunderlying layer for magnetic layer may be provided below the magneticlayer such that the underlying layer for magnetic layer is brought intocontact with the vertical bias layer. A vertical bias layer protectivelayer may be provided on the vertical bias layer such that the verticalbias layer protective layer is brought into contact with the magneticlayer or the underlying layer for magnetic layer.

This allows the vertical bias layer to apply a vertical bias magneticfield more positively and effectively to the magnetic layer.

A magneto-resistance effect element according to the present inventioncomprises a lower conductive layer, a fixed layer provided on the lowerconductive layer and having a pined orientation of magnetization, and anon-magnetic layer provided on the fixed layer. The magneto-resistanceeffect element also comprises a free layer provided on the non-magneticlayer and having an orientation of magnetization varied by a magneticfield applied thereto, a magnetic layer provided on the free layer andmagnetically coupled to the free layer, and a vertical bias layer forapplying a magnetic field to the magnetic layer. The magneto-resistanceeffect element is adapted that a sense current for detecting a change inelectrical resistance of the non-magnetic layer flows substantially inperpendicular relation to the non-magnetic layer.

In addition, a fixing layer for pinning the orientation of magnetizationof the fixed layer may be provided below the fixed layer.

Furthermore, it is preferable that at least part of the magnetic layeris brought into direct contact with the vertical bias layer.Alternatively, the underlying layer for magnetic layer may be providedbelow the magnetic layer such that the underlying layer for magneticlayer is brought into contact with the vertical bias layer. A verticalbias layer protective layer may be provided on the vertical bias layersuch that the vertical bias layer protective layer is brought intocontact with the magnetic layer or the underlying layer for magneticlayer.

In addition, the magnetic layer can be magnetically coupled to the freelayer by anti-ferromagnetic coupling or ferromagnetic coupling.Furthermore, the second non-magnetic layer may be provided between themagnetic layer and the free layer.

A magneto-resistance effect element according to the present inventioncomprises a lower conductive layer, a fixed layer provided on the lowerconductive layer and having a pinned orientation of magnetization, and afirst non-magnetic layer provided on the fixed layer. Themagneto-resistance effect element also comprises a free layer providedon the first non-magnetic layer and having an orientation ofmagnetization varied by a magnetic field applied thereto. Themagneto-resistance effect element further comprises a first magneticlayer provided on the free layer and magnetically coupled to the freelayer, a second magnetic layer provided on the first magnetic layer andmagnetically coupled to the first magnetic layer, and a vertical biaslayer for applying a magnetic field to the first and second magneticlayers. The magneto-resistance effect element is adapted that a sensecurrent for detecting a change in electrical resistance of the firstnon-magnetic layer flows substantially in perpendicular relation to thefirst non-magnetic layer.

In addition, the first magnetic layer and the second magnetic layer areequal to or greater than the free layer in length in the direction ofthe magnetic field applied by the vertical bias layer, respectively.

Furthermore, a second non-magnetic layer can be provided between thefree layer and the first magnetic layer, while a third non-magneticlayer can be provided between the first magnetic layer and the secondmagnetic layer. In addition, an underlying layer for fixing layer may beprovided under the fixing layer.

In the present invention, a vertical bias magnetic field can be onceapplied to a three-layered film made up of the first magnetic layer, thethird non-magnetic layer, and the second magnetic layer, from thevertical bias layer and then to the free layer from the three-layeredfilm. As described above, the vertical bias magnetic field is applied tothe free layer from the vertical bias layer through two steps, therebyfacilitating the control of the vertical bias magnetic field applied tothe free layer.

Still furthermore, the product of saturation magnetization and filmthickness of the first magnetic layer can be substantially equal to theproduct of saturation magnetization and film thickness of the secondmagnetic layer, and the three-layered film made up of the first magneticlayer, the third non-magnetic layer, and the second magnetic layer canbe a layered antiferromagnetic body.

This eliminates the sensitivity of the three-layered film to magneticfields but provides only the free layer with the sensitivity to magneticfields. For this reason, when the magneto-resistance effect element isincorporated into a read head, the read track width is determined onlyby the width of the free layer, thus making it possible to prevent thebroadening of the effective track width. Incidentally, “beingsubstantially equal” means “being equal to such an extent that an effectof reduction in sensitivity of the three-layered film to magnetic fieldscan be recognized”.

In addition, it is desirable that at least part of the first magneticlayer is in direct contact with the vertical bias layer. Alternatively,a first underlying layer for magnetic layer may be provided below thefirst magnetic layer such that the first underlying layer for magneticlayer is brought into contact with the vertical bias layer. A verticalbias layer protective layer may be provided on the vertical bias layersuch that the vertical bias layer protective layer is brought intocontact with the first magnetic layer or the first underlying layer formagnetic layer. Similarly, it is desirable that at least part of thesecond magnetic layer is in direct contact with the vertical bias layer.Alternatively, a second underlying layer for magnetic layer may beprovided below the second magnetic layer such that the second underlyinglayer for magnetic layer is brought into contact with the vertical biaslayer. The vertical bias layer protective layer may also be brought intocontact with the second magnetic layer or the second underlying layerfor magnetic layer.

A magneto-resistance effect element according to the present inventioncomprises a lower conductive layer, a fixed layer provided on the lowerconductive layer and having a pinned orientation of magnetization, and anon-magnetic layer provided on the fixed layer. The magneto-resistanceeffect element also comprises a free layer provided on the non-magneticlayer and having an orientation of magnetization varied by a magneticfield applied thereto, a magnetic layer provided on the free layer, anda vertical bias layer, provided on the magnetic layer, for applying amagnetic field to the magnetic layer. The magneto-resistance effectelement is adapted that a sense current for detecting a change inelectrical resistance of the non-magnetic layer flows substantially inperpendicular relation to the non-magnetic layer.

A magneto-resistance effect element according to the present inventioncomprises a lower conductive layer, a first fixed layer provided on thelower conductive layer and having a pinned orientation of magnetization,and a first non-magnetic layer provided on the first fixed layer. Themagneto-resistance effect element also comprises a first free layerprovided on the first non-magnetic layer and having an orientation ofmagnetization varied by a magnetic field applied thereto. Themagneto-resistance effect element further comprises a magnetic layerprovided on the first free layer and magnetically coupled to the firstfree layer, and a second free layer provided on the magnetic layer andmagnetically coupled to the magnetic layer. The magneto-resistanceeffect element also comprises a second non-magnetic layer provided onthe second free layer, a second fixed layer provided on the secondnon-magnetic layer and having a pinned orientation of magnetization, anda vertical bias layer for applying a magnetic field to the magneticlayer. The magneto-resistance effect element is adapted that a sensecurrent for detecting a change in electrical resistance of the first andsecond non-magnetic layers flows substantially in perpendicular relationto the first and second non-magnetic layers.

In addition, it is preferable that the magnetic layer is equal to orgreater than the first and second free layers in length in the directionof the magnetic field applied by the vertical bias layer.

In the present invention, two pairs of free layers and fixed layers areprovided to be vertically symmetric. This makes it possible to cancelout the effects of the magnetic field caused by sense current flowingthrough the free layers and the fixed layers, thereby providing a linearresponse to the magnetic field.

In addition, the first fixing layer for pinning the orientation ofmagnetization of the first fixed layer may be disposed below the firstfixed layer, while the second fixing layer for pinning the orientationof magnetization of the second fixed layer may be disposed above thesecond fixed layer. Furthermore, the first underlying layer for fixinglayer may be provided below the first fixing layer.

In addition, the first free layer can be magnetically coupled to themagnetic layer by anti-ferromagnetic coupling or ferromagnetic coupling.Furthermore, the third non-magnetic layer may be provided between thefirst free layer and the magnetic layer. Likewise, the magnetic layercan be magnetically coupled to the second free layer byanti-ferromagnetic coupling or ferromagnetic coupling. Furthermore, afourth non-magnetic layer may be provided between the magnetic layer andthe second free layer.

In addition, it is preferable that at least part of the magnetic layeris in direct contact with the vertical bias layer. Alternatively, theunderlying layer for magnetic layer may be provided below the magneticlayer such that the underlying layer for magnetic layer is brought intocontact with the vertical bias layer. A vertical bias layer protectivelayer may be provided on the vertical bias layer such that the verticalbias layer protective layer is brought into contact with the magneticlayer or the underlying layer for magnetic layer.

A magneto-resistance effect element according to the present inventioncomprises a lower conductive layer, a first magnetic layer provided onthe lower electrically conductive, and a second magnetic layer providedon the first magnetic layer and magnetically coupled to the firstmagnetic layer. The magneto-resistance effect element also comprises afree layer provided on the second magnetic layer, magnetically coupledto the second magnetic layer, and having an orientation of magnetizationvaried by a magnetic field applied thereto. The magneto-resistanceeffect element further comprises a first non-magnetic layer provided onthe free layer, a fixed layer provided on the first non-magnetic layerand having a pinned orientation of magnetization, and a vertical biaslayer for applying a magnetic field to the first magnetic layer. Themagneto-resistance effect element is adapted that a sense current fordetecting a change in electrical resistance of the first non-magneticlayer flows substantially in perpendicular relation to the firstnon-magnetic layer.

In addition, it is preferable that the first magnetic layer is equal toor greater than the free layer in length in the direction of themagnetic field applied by the vertical bias layer. It is also preferablethat the second magnetic layer is equal to or greater than the freelayer in length in the direction of the magnetic field applied by thevertical bias layer.

Furthermore, a fixing layer for pinning the orientation of magnetizationof the fixed layer may be disposed below the fixed layer.

Still furthermore, the first magnetic layer can be magnetically coupledto the second magnetic layer by anti-ferromagnetic coupling orferromagnetic coupling. Furthermore, a second non-magnetic layer may bedisposed between the first magnetic layer and the second magnetic layer.Likewise, the second magnetic layer can be magnetically coupled to thefree layer by anti-ferromagnetic coupling or ferromagnetic coupling.Furthermore, a third non-magnetic layer may be disposed between thesecond magnetic layer and the free layer.

Still furthermore, it is preferable that the product of saturationmagnetization and film thickness of the first magnetic layer issubstantially equal to the product of saturation magnetization and filmthickness of the second magnetic layer. It is also preferable that athree-layered film made up of the first magnetic layer, the secondnon-magnetic layer, and the second magnetic layer is a layeredantiferromagnetic body.

Still furthermore, it is preferable that at least part of the firstmagnetic layer is in direct contact with the vertical bias layer.Alternatively, a first underlying layer for magnetic layer may beprovided below the first magnetic layer such that the underlying layerfor magnetic layer is brought into contact with the vertical bias layer.A vertical bias layer protective layer may be provided on the verticalbias layer such that the vertical bias layer protective layer is broughtinto contact with the magnetic layer or the underlying layer formagnetic layer. Likewise, it is preferable that at least part of thesecond magnetic layer is in direct contact with the vertical bias layer.Alternatively, an upper layer may be provided on the second magneticlayer such that the upper layer is brought into contact with thevertical bias layer. The vertical bias layer protective layer may beprovided below the vertical bias layer such that the vertical bias layerprotective layer is brought into contact with the magnetic layer or theupper layer.

A magneto-resistance effect element according to the present inventioncomprises a lower conductive layer, a vertical bias layer provided onthe lower conductive layer, a first magnetic layer provided on thevertical bias layer, and a second magnetic layer provided on the firstmagnetic layer and magnetically coupled to the first magnetic layer. Themagneto-resistance effect element also comprises a free layer providedon the second magnetic layer, magnetically coupled to the secondmagnetic layer, and having an orientation of magnetization varied by amagnetic field applied thereto. The magneto-resistance effect elementfurther comprises a first non-magnetic layer provided on the free layer,and a fixed layer provided on the first non-magnetic layer and having apinned orientation of magnetization. The magneto-resistance effectelement is adapted that a sense current for detecting a change inelectrical resistance of the first non-magnetic layer flowssubstantially in perpendicular relation to the first non-magnetic layer.

In addition, it is preferable that the first magnetic layer is equal toor greater than the free layer in length in the direction of themagnetic field applied by the vertical bias layer. It is also preferablethat the second magnetic layer is equal to or greater than the freelayer in length in the direction of the magnetic field applied by thevertical bias layer. Furthermore, an underlying layer for vertical biaslayer may be provided below the vertical bias layer.

Still furthermore, the first magnetic layer can be magnetically coupledto the second magnetic layer by anti-ferromagnetic coupling orferromagnetic coupling. Furthermore, a second non-magnetic layer may beprovided between the first magnetic layer and the second magnetic layer.Likewise, the second magnetic layer can be magnetically coupled to thefree layer by anti-ferromagnetic coupling or ferromagnetic coupling.Furthermore, a third non-magnetic layer may be provided between thesecond magnetic layer and the free layer.

Still furthermore, it is preferable that the product of saturationmagnetization and film thickness of the first magnetic layer issubstantially equal to the product of saturation magnetization and filmthickness of the second magnetic layer. It is preferable that athree-layered film made up of the first magnetic layer, the secondnon-magnetic layer, and the second magnetic layer is a layeredantiferromagnetic body.

Still furthermore, it is preferable that at least part of the firstmagnetic layer is in direct contact with the vertical bias layer.Alternatively, an underlying layer for magnetic layer may be providedbelow the first magnetic layer such that the underlying layer formagnetic layer is brought into contact with the vertical bias layer. Avertical bias layer protective layer may be provided on the verticalbias layer such that the vertical bias layer protective layer is broughtinto contact with the magnetic layer or the underlying layer formagnetic layer. Similarly, it is desirable that at least part of thesecond magnetic layer is in direct contact with the vertical bias layer.Alternatively, an upper layer may be provided on the second magneticlayer such that the upper layer is brought into contact with thevertical bias layer. An underlying layer for vertical bias layer may beprovided below the vertical bias layer such that the underlying layerfor vertical bias layer is brought into contact with the magnetic layeror the upper layer.

A magneto-resistance effect head according to the present inventioncomprises the magneto-resistance effect element and a lower shield layerserving as a substrate for the magneto-resistance effect element. Themagneto-resistance effect head also comprises an upper conductive layer,provided on the magneto-resistance effect element, for inputting a sensecurrent for detecting a change in electrical resistance of themagneto-resistance effect element into the magneto-resistance effectelement; and an upper shield layer provided on the upper electricallyconductive.

A magneto-resistance transducer system according to the presentinvention comprises the magneto-resistance effect head, an electriccurrent generator circuit for supplying a sense current to themagneto-resistance effect head, and a data read circuit for detecting achange in electrical resistance of the magneto-resistance effect head todetermine a magnetic field applied to the magneto-resistance effecthead.

A magnetic storage system according to the present invention comprisesthe magneto-resistance transducer system and a magnetic storage mediumhaving a plurality of tracks for allowing the magneto-resistancetransducer system to write and read data thereon. The magnetic storagesystem also comprises a first actuator for moving the magneto-resistancetransducer system to where a selected track is located in the magneticstorage medium, and a second actuator for rotatably driving the track.

The present invention makes it possible to provide a magneto-resistanceeffect head which has reduced noise in the read signal waveform andimproved (S/N) ratio and bit error rate in comparison with the priorart. It is also possible to employ the magneto-resistance effect head toprovide a high-performance magnetic read/write device and a magneticmemory device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to a prior-art;

FIG. 2 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to a prior-art;

FIG. 3 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to a prior-art;

FIGS. 4-10 are fragmentary sectional views illustrating a method forfabricating a magneto-resistance effect head according to a firstembodiment of the present invention;

FIG. 11 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to a variation of thisembodiment;

FIG. 12 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to another variation of thisembodiment;

FIGS. 13-21 are fragmentary sectional views illustrating a method forfabricating a magneto-resistance effect head according to a secondembodiment of the present invention;

FIGS. 22-28 are fragmentary sectional views illustrating a method forfabricating a magneto-resistance effect head according to a thirdembodiment of the present invention;

FIGS. 29-31 are fragmentary sectional views illustrating a method forfabricating a magneto-resistance effect head according to a fourthembodiment of the present invention;

FIG. 32 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to a variation of thisembodiment;

FIG. 33 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to another variation of thisembodiment;

FIGS. 34-37 are fragmentary sectional views illustrating a method forfabricating a magneto-resistance effect head according to a fifthembodiment of the present invention;

FIGS. 38-42 are fragmentary sectional views illustrating a method forfabricating a magneto-resistance effect head according to a sixthembodiment of the present invention;

FIGS. 43-49 are fragmentary sectional views illustrating a method forfabricating a magneto-resistance effect head according to a seventhembodiment of the present invention;

FIG. 50 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to a variation of thisembodiment;

FIG. 51 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to another variation of thisembodiment;

FIG. 52 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to still another variation ofthis embodiment;

FIG. 53 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to still another variation ofthis embodiment;

FIG. 54 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to still another variation ofthis embodiment;

FIG. 55 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to still another variation ofthis embodiment;

FIG. 56 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to still another variation ofthis embodiment;

FIG. 57 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to still another variation ofthis embodiment;

FIGS. 58-64 are fragmentary sectional views illustrating a method forfabricating a magneto-resistance effect head according to an eighthembodiment of the present invention;

FIG. 65 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to a variation of thisembodiment;

FIG. 66 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to another variation of thisembodiment;

FIGS. 67-70 are fragmentary sectional views illustrating a method forfabricating a magneto-resistance effect head according to a ninthembodiment of the present invention;

FIGS. 71-76 are fragmentary sectional views illustrating a method forfabricating a magneto-resistance effect head according to a tenthembodiment of the present invention;

FIG. 77 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to a variation of thisembodiment;

FIGS. 78-87 are fragmentary sectional views illustrating a method forfabricating a magneto-resistance effect head according to an eleventhembodiment of the present invention;

FIG. 88 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to a variation of thisembodiment;

FIG. 89 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to another variation of thisembodiment;

FIG. 90 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to still another variation ofthis embodiment;

FIGS. 91-94 are fragmentary sectional views illustrating a method forfabricating a magneto-resistance effect head according to a twelfthembodiment of the present invention;

FIG. 95 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to a variation of thisembodiment;

FIG. 96 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to another variation of thisembodiment;

FIGS. 97-102 are fragmentary sectional views illustrating a method forfabricating a magneto-resistance effect head according to a thirteenthembodiment of the present invention;

FIG. 103 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to a variation of thisembodiment;

FIG. 104 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect head according to another variation of thisembodiment;

FIG. 105 is a perspective view illustrating the structure of a magneticread/write head according to a fourteenth embodiment of the presentinvention;

FIG. 106 is a schematic view illustrating the structure of amagneto-resistance transducer system according to this embodiment;

FIG. 107 is a block view illustrating the structure of a magneticstorage system according to this embodiment; and

FIG. 108 is a perspective view illustrating the structure of a magneticstorage system according to this embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, the present invention will be explained below more specificallywith reference to the accompanying drawings in accordance with theembodiments. Incidentally, all the fragmentary sectional views employedin the embodiments of the present invention illustrate amagneto-resistance effect head cut in parallel to the surface of an airbearing. In addition, in the embodiments of the present invention, theexpression of “patterning” of layers or the like denotes allowing partof the layers or the like to remain and part thereof to be removed byetching or like means in illustrated regions within illustratedsections. Thus, this expression will never mean allowing part of thelayers or the like to remain and part thereof to be removed by etchingor like means in non-illustrated sections or regions. In other words, inthe embodiments of the present invention, the layers or the like thatare not denoted with the expression of “patterning” may also allow partthereof to remain and part thereof to be removed by etching or likemeans in non-illustrated sections or regions.

Now, described below are a magneto-resistance effect head according to afirst embodiment of the present invention and a method for fabricatingthe head. FIGS. 4-10 are fragmentary sectional views illustrating thesteps of the method for fabricating the magneto-resistance effect headaccording to this embodiment in the order in which they appear in themethod.

First, as shown in FIG. 4, a lower shield layer 16 and a lowerconductive layer 1 are formed successively on a substrate (not shown).

Then, as shown in FIG. 5, a photoresist 20 having an opening portion 20a is formed on the lower conductive layer 1, which is in turn etched bydry etching or like means to form a recessed portion 1 a on the surfaceof lower conductive layer 1.

Then, as shown in FIG. 6, on the recessed portion 1 a of the lowerconductive layer 1, deposited are an underlying layer for vertical biaslayer 2 a and a vertical bias layer 2 b so as to be partially buried inthe recessed portion of the lower conductive layer 1, and thereafter thephotoresist 20 is removed.

Then, as shown in FIG. 7, on the lower conductive layer 1 and thevertical bias layer 2 b, formed and stacked in the following order arean underlying layer for free layer 3 a, a the free layer 3 b, anon-magnetic layer 4, a fixed layer 5, a fixing layer 6 b, and an upperlayer 7.

Then, as shown in FIG. 8, there is formed a photoresist 21 immediatelybelow the upper surface of the upper layer 7 so as to cover the centralportion of the region where the vertical bias layer 2 b is not formed.Then, with the photoresist 21 being employed as a mask, the non-magneticlayer 4, the fixed layer 5, the fixing layer 6 b, and the upper layer 7are etched by dry etching or the like to form an insulation layer 11 soas to be buried in the etched portion. At this time, the upper surfaceof the upper layer 7 is exposed on the upper surface of the insulationlayer 11.

Then, as shown in FIG. 9, the photoresist 21 is removed. Then, amagneto-resistance effect element 31 a is formed which is made up of thelower conductive layer 1, the underlying layer for vertical bias layer 2a, the vertical bias layer 2 b, the underlying layer for free layer 3 a,the free layer 3 b, the non-magnetic layer 4, the fixed layer 5, thefixing layer 6 b, and the upper layer.

Then, as shown in FIG. 10, there is deposited an upper conductive layer15 on the upper layer 7 and the insulation layer 11, and a photoresist(not shown) is formed, which is in turn employed as a mask to patternthe upper conductive layer 15 by dry etching or the like. Thereafter,the photoresist is removed on which formed is an upper shield layer 17,thereby forming a magneto-resistance effect head 61 a.

Now, the structure of the magneto-resistance effect head 61 a accordingto this embodiment is described. As shown in FIG. 10, provided are thelower shield layer 16 and the lower conductive layer 1. The lowerconductive layer 1 has the recessed portion 1 a, and the recessedportion 1 a is provided with the underlying layer for vertical biaslayer 2 a and the vertical bias layer 2 b. The underlying layer for freelayer 3 a and the free layer 3 b are provided in the portion of thelower conductive layer 1, where provided is neither the underlying layerfor vertical bias layer 2 a nor the vertical bias layer 2 b, and on thevertical bias layer 2 b. On top of the free layer 3 b, formed in thefollowing order are the non-magnetic layer 4 patterned so as not to bedisposed immediately above the vertical bias layer 2 b, the fixed layer5, the fixing layer 6 b, and the upper layer 7.

In addition, the non-magnetic layer 4, the fixed layer 5, the fixinglayer 6 b, and the upper layer 7 are buried in the insulation layer 11,and the upper surface of the upper layer 7 is exposed to the uppersurface of the insulation layer 11. Furthermore, on top of the upperlayer 7 and the insulation layer 11, provided is the upper conductivelayer 15, on top of which the upper shield layer 17 is formed.

In the aforementioned structure, the lower conductive layer 1 and theupper conductive layer 15 act as the upper and lower electrodes forconducting a sense current in the direction perpendicular to stackedlayer planes. Here, the stacked layer planes are formed of theunderlying layer for free layer 3 a disposed between the lowerconductive layer 1 and the upper conductive layer 15, the free layer 3b, the non-magnetic layer 4, the fixed layer 5, the fixing layer 6 b,and the upper layer 7. Materials forming the lower conductive layer 1and the upper conductive layer 15 include a single material of one type,a mixture of materials of two or more types, a compound of materials oftwo or more types, or a multi-layered film formed of materials of two ormore types, which are selected from the group consisting of Au, Ag, Cu,Mo, W, Y, Ti, Zr, Hf, V, Nb, Pt, and Ta. In particular, Au, Ag, Cu, Pt,and Ta are more favorable. In addition, materials forming the substrateinclude an altic, SiC, and alumina.

In addition, the vertical bias layer 2 b is to apply a vertical biasmagnetic field to the free layer 3 b, while the underlying layer forvertical bias layer 2 a is to improve the film quality such as thecrystallization property of the vertical bias layer 2 b and the magneticproperties of the vertical bias layer 2 b. Materials forming theunderlying layer for vertical bias layer 2 a include a single materialof one type, a mixture of materials of two or more types, or amulti-layered film formed of materials of two or more types, which areselected from the group consisting of Ta, Hf, Zr, W, Cr, Ti, Mo, Pt, Ni,Ir, Cu, Ag, Co, Zn, Ru, Rh, Re, Au, Os, Pd, Nb, V, Fe, FeCo, FeCoNi, andNiFe. In particular, Cr, Fe, and CoFe are more favorable. On the otherhand, materials forming the vertical bias layer 2 b include a singlematerial of one type, a mixture of materials of two or more types, or amulti-layered film formed of materials of two or more types, which areselected from the group consisting of CoCrPt, CoCr, CoPt, CoCrTa, FeMn,NiMn, Ni oxide, NiCo oxide, Fe oxide, NiFe oxide, IrMn, PtMn, PtPdMn,ReMn, Co ferrite, and Ba ferrite. In particular, CoCrPt, CoCrTa, CoPt,NiMn, and IrMn are more favorable.

When an external magnetic field is applied to a magnetic sensorincluding the magneto-resistance effect head 61 a, the free layer 3 bacting as a magnetic layer changes the orientation of magnetization inaccordance with the direction and the magnitude of the magnetic field.An external magnetic field is applied to the free layer 3 b via thevertical bias layer 2 b. In addition, the underlying layer for freelayer 3 a is to improve the film quality such as the crystallizationproperty of the free layer 3 b and the magnetic properties of the freelayer 3 b. Materials forming the underlying layer for free layer 3 ainclude a single material of one type, a mixture of materials of two ormore types, a compound of materials of two or more types, or amulti-layered film formed of materials of two or more types, which areselected from the group consisting of Ta, Hf, Zr, W, Cr, Ti, Mo, Pt, Ni,Ir, Cu, Ag, Co, Zn, Ru, Rh, Re, Au, Os, Pd, Nb, and V. In particular,Ta, Zr, and Hf are more favorable. Materials forming the free layer 3 binclude alloys and amorphous magnetic materials such as NiFe, CoFe,NiFeCo, FeCo, CoFeB, CoZrMo, CoZrNb, CoZr, CoZrTa, CoHf, CoTa, CoTaHf,CoNbHf, CoZrNb, CoHfPd, CoTaZrNb, and CoZrMoNi. As an additive element,one or more types of elements selected from the group consisting of Ta,Hf, Zr, W, Cr, Ti, Mo, Pt, Ni, Ir, Cu, Ag, Co, Zn, Ru, Rh, Re, Au, Os,Pd, Nb, and V can also be employed. More favorable are NiFe, a two-layerfilm of NiFe/CoFe, a two-layer film of NiFe/NiFeCo, and a two-layer filmof NiFe/Co.

The fixing layer 6 b is to pin the orientation of magnetization of thefixed layer 5, while the underlying layer for fixing layer 6 a is toimprove the film quality such as the crystallization property of thefixing layer 6 b and the magnetic properties of the fixing layer 6 b. Onthe other hand, the fixed layer 5 has an orientation of magnetizationthat is pinned by the fixing layer 6 b.

Materials forming the underlying layer for fixing layer 6 a include asingle material of one type, a mixture of materials of two or moretypes, a compound of materials of two or more types, or a multi-layeredfilm formed of materials of two or more types, which are selected fromthe group consisting of Ta, Hf, Zr, W, Cr, Ti, Mo, Pt, Ni, Ir, Cu, Ag,Co, Zn, Ru, Rh, Re, Au, Os, Pd, Nb, and V. In particular, Ta, Zr, and Hfare more favorable. On the other hand, as a material for the fixinglayer 6 b, it is possible to employ FeMn, NiMn, IrMn, RhMn, PtPdMn,ReMn, PtMn, PtCrMn, CrMn, CrAl, TbCo, CoCr, CoCrPt, CoCrTa, PtCo and thelike. In particular, a favorable material is PtMn or PtMn to which dopedis at least one type of element selected from the group consisting ofTi, V, Cr, Co, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Hf, Ta, W, Re,Os, Ir, Pt, Au, Si, and Al.

As materials forming the fixed layer 5, it is possible to use alloys andamorphous magnetic materials such as NiFe, Co, CoFe, NiFeCo, FeCo,CoFeB, CoZrMo, CoZrNb, CoZr, CoZrTa, CoTa, CoTaHf, CoNbHf, CoZrNb,CoHfPd, CoTaZrNb, and CoZrMoNi. In addition, it is also possible to usea layered film of those materials combined with at least one type ofmetal or an alloy of the metals selected from the group consisting ofTi, V, Cr, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ra, Rh, Pd, Ag, Hf, Ta, W, Re, Os,Ir, Pt, Au, Si, Al, and Ni. In particular, three-layer films such asCo/Ru/Co, CoFe/Ru/CoFe, CoFeNi/Ru/CoFeNi, Co/Cr/Co. CoFe/Cr/CoFe, andCoFeNi/Cr/CoFeNi are favorable.

Then, non-magnetic layer 4 is disposed between the free layer 3 b andthe fixed layer 5, varying in electrical resistance in accordance withthe angle between the orientation of magnetization of the free layer 3 band that of the fixed layer 5. As materials forming the non-magneticlayer 4, used are metal, oxide, nitride, a mixture of oxide and nitride,a multi-layered film of metal and oxide, a multi-layered film of metaland nitride, or a multi-layered film a mixture of metal, oxide, andnitride. And, the metals include at least one type of metal selectedfrom the group consisting of Ti, V, Cr, Co, Cu, Zn, Y, Zr, Nb, Mo, Tc,Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au, Si, Al, Ti, Ta, Pt, Ni,Co, Re, and V. The oxides are formed of these metals and the nitridesare also formed of these metals. In particular, Al oxide and Cu arefavorable.

In addition, the upper layer 7 is to prevent the layer disposedthereunder from being corroded during the processes for fabricating themagneto-resistance effect head 61 a and in the service environment.Materials forming the upper layer 7 include a single material of onetype, a mixture of materials of two or more types, a compound ofmaterials of two or more types, or a multi-layered film formed ofmaterials of two or more types, which are selected from the groupconsisting of Au, Ag, Cu, Mo, W, Y, Ti, Pt, Zr, Hf, V, Nb, Ta, and Ru.In particular, Ta, Zr, and Ti are favorable.

Furthermore, the insulation layer 11 is to prevent the leakage of asense current flowing through the non-magnetic layer 4. Materialsforming the insulation layer 11 include a single material, a mixture ofmaterials, and a multi-layered film formed of materials, which areselected from the group consisting of Al oxide, Si oxide, aluminumnitride, silicon nitride, and diamond-like carbon.

Still furthermore, materials forming the lower shield layer 16 and theupper shield layer 17 include a single material of one type, a mixtureof materials of two or more types, or a multi-layered film formed ofmaterials of two or more types, which are selected from the groupconsisting of NiFe, CoZr, CoFeB, CoZrMo, CoZrNb, CoZrTa, CoHf, CoTa,CoTaHf, CoNbHf, CoZrNb, CoHfPd, CoTaZrNb, CoZrMoNi, FeAlSi, a Fe nitridebase material, MnZn ferrite, NiZn ferrite, and Mgzn ferrite.

Now, the operation of the magneto-resistance effect head 61 a isexplained below. When an external magnetic field is applied to themagneto-resistance effect head 61 a, a magnetic field is applied to thefree layer 3 b via the vertical bias layer 2 b, causing the orientationof magnetization of the free layer 3 b to change in accordance with thedirection and magnitude of the magnetic field applied thereto. And,since the orientation of magnetization of the fixed layer 5 is pinned bythe fixing layer 6 b, a change occurs in orientation of magnetizationbetween the fixed layer 5 and the free layer 3 b, causing a change inelectrical resistance of the non-magnetic layer 4. In this state, thelower conductive layer 1 and the upper conductive layer 15 allow a sensecurrent to flow in the direction perpendicular to the non-magnetic layer4 to measure the electrical resistance of the non-magnetic layer 4,thereby making it possible to detect the external magnetic field.

Now, an effect of this embodiment is described. As shown in FIG. 10, themagneto-resistance effect head 61 a according to this embodiment has thefree layer 3 b which is greater than the fixed layer 5 in length, andonly the free layer 3 b is disposed near the vertical bias layer 2 b.This allows the vertical bias layer 2 b to apply a magnetic fieldpositively and effectively to the free layer 3 b and makes it possibleto prevent the leakage of a sense current from the fixed layer 5 to thevertical bias layer 2 b. This allows almost all the sense currentapplied to flow through the non-magnetic layer 4, thereby improving theperformance of the magneto-resistance effect head 61 a.

Furthermore, part of the direction of thickness of the patternedunderlying layer for vertical bias layer 2 a and the vertical bias layer2 b is buried in the recessed portion 1 a of the lower conductive layer1. This provides a gradual slope to the end portion of the underlyinglayer for vertical bias layer 2 a and the vertical bias layer 2 b,thereby allowing the vertical bias layer 2 b to apply a vertical biasmagnetic field to the free layer 3 b more effectively.

FIGS. 11 and 12 are fragmentary sectional views illustrating a variationof the magneto-resistance effect element according to this embodiment.FIG. 11 illustrates a magneto-resistance effect element 31 b having thefree layer 3 b patterned to bring the end portion thereof into contactwith that of the vertical bias layer 2 b.

On the other hand, FIG. 12 illustrates a magneto-resistance effectelement 31 c having the free layer 3 b patterned to make the end portionthereof overlap that of the vertical bias layer 2 b. Like themagneto-resistance effect element 31 a, the magneto-resistance effectelement 31 c shown in FIGS. 11, 12 can constitute the magneto-resistanceeffect head.

Incidentally, this embodiment has shown that the non-magnetic layer 4 ispatterned in conjunction with the fixed layer 5, the fixing layer 6 b,and the upper layer 7. However, the non-magnetic layer 4 can be extendedlike the free layer 3 b. Alternatively, the non-magnetic layer 4 may bepatterned to be larger than the fixing layer 6 b and the fixing layer 6b and smaller than the free layer 3 b.

In addition, the underlying layer for vertical bias layer 2 a, theunderlying layer for free layer 3 a, and the upper layer 7 may beomitted, and a protective layer for protecting the vertical bias layermay be provided on top of the vertical bias layer 2 b.

Furthermore, this embodiment has shown that the lower shield layer 16and the lower conductive layer 1 are provided separately. However, thelower shield layer 16 and lower conductive layer 1 may be a commonlayer. In this case, the lower conductive layer 1 is omitted. Inaddition, the upper conductive layer 15 and the upper shield 17 may be acommon layer. In this case, the upper conductive layer 15 is omitted.This allows the gap between the top and bottom shield layers to be madesmaller. Furthermore, an upper gap layer may be provided between theupper conductive layer 15 and the shield layer 17 or a lower gap layermay be provided between the lower shield layer 16 and the lowerconductive layer 1.

Now, a second embodiment of the present invention is described below.FIGS. 13-21 are fragmentary sectional views illustrating the steps of amethod for fabricating a magneto-resistance effect head according tothis embodiment in the order in which they appear.

First, as shown in FIG. 13, the lower shield layer 16 and the lowerconductive layer 1 are successively formed on a substrate (not shown).

Then, as shown in FIG. 14, the photoresist 20 having the opening portion20 a is formed on top of the lower conductive layer 1 which is etched bydry etching or like means to form the recessed portion 1 a on thesurface of the lower conductive layer 1.

Then, as shown in FIG. 15, the underlying layer for vertical bias layer2 a and the vertical bias layer 2 b are deposited on top of the lowerconductive layer 1 after the photoresist 20 has been removed.

Then, as shown in FIG. 16, the photoresist 21 is formed to cover theregion having the recessed portion 1 a arranged immediately below thevertical bias layer 2 b and provide an opening portion 21 a for theregion having no recessed portion 1 a arranged immediately below thevertical bias layer 2 b. Subsequently, with the photoresist 21 beingemployed as a mask, the underlying layer for vertical bias layer 2 a andthe vertical bias layer 2 b are etched and thereby patterned by dryetching or like means.

Then, as shown in FIG. 17, on top of the lower conductive layer 1 andvertical bias layer 2 b, formed and layered in the following order arethe underlying layer for free layer 3 a, the free layer 3 b, thenon-magnetic layer 4, the fixed layer 5, the fixing layer 6 b, and theupper layer 7.

Then, as shown in FIG. 18, a photoresist 22 is provided to cover theregion having no vertical bias layer 2 b arranged immediately below theupper layer 7. With the photoresist 22 being employed as a mask, theunderlying layer for free layer 3 a, the free layer 3 b, thenon-magnetic layer 4, the fixed layer 5, the fixing layer 6 b, and theupper layer 7 are patterned by dry etching or like means.

Then, as shown in FIG. 19, the photoresist 22 is removed to form aphotoresist 23 on top of the upper layer 7 to cover the central portionof the upper layer 7. With the photoresist 23 being employed as a mask,the non-magnetic layer 4, the fixed layer 5, the fixing layer 6 b, andthe upper layer 7 are patterned by dry etching or like means.

Then, as shown in FIG. 20, the periphery of the pattern of thenon-magnetic layer 4, the fixed layer 5, the fixing layer 6 b, and theupper layer 7 is buried in the insulation layer 11, thereby forming amagneto-resistance effect element 32 a. Then, as shown in FIG. 21, afterthe photoresist 23 has been removed, the upper conductive layer 15 isdeposited on top of the upper layer 7 and the insulation layer 11 andthen a photoresist (not shown) is formed. With this photoresist beingemployed as a mask, the upper conductive layer 15 is patterned by dryetching or like means. Then, this photoresist is removed to form theupper shield layer 17 thereon and thus a magneto-resistance effect head62 a is formed.

Now, the structure of the magneto-resistance effect head 62 a accordingto this embodiment is described below. As shown in FIG. 21, themagneto-resistance effect head 62 a according to this embodiment has adifferent shape of the underlying layer for free layer 3 a and the freelayer 3 b in comparison with the magneto-resistance effect head 61 aaccording to the first embodiment shown in FIG. 10. In this embodiment,the end portion of the underlying layer for free layer 3 a and the freelayer 3 b are flush and in contact with that of the underlying layer forvertical bias layer 2 a and the vertical bias layer 2 b. In themagneto-resistance effect head 62 a according to this embodiment, thestructure and operation thereof is the same as those of themagneto-resistance effect head 61 a according to the aforementionedfirst embodiment except for the shape of the underlying layer for freelayer 3 a and the free layer 3 b.

Incidentally, in this embodiment, it has been explained in which thenon-magnetic layer 4 is patterned in conjunction with the fixed layer 5,the fixing layer 6 b, and the upper layer 7. However, like the firstembodiment, the non-magnetic layer 4 may be extended as the free layer 3b. Alternatively, the non-magnetic layer 4 may be patterned to be largerthan the pattern of the fixed layer 5, the fixing layer 6 b, and theupper layer 7, and smaller than the pattern of the free layer 3 b.

Furthermore, in this embodiment, it has been explained in which theupper conductive layer 15 is patterned, however, the upper conductivelayer 15 may be extended without being patterned.

Now, described below is a third embodiment according to the presentinvention. FIGS. 22-28 are fragmentary sectional views illustrating thesteps of a method for fabricating a magneto-resistance effect headaccording to this embodiment in the order in which they appear.

First, as shown in FIG. 22, the lower shield layer 16 and the lowerconductive layer 1 are successively formed on a substrate (not shown).

Then, as shown in FIG. 23, the photoresist 20 having the opening portion20 a is formed on top of the lower conductive layer 1, which is thenetched by dry etching or like means to form the recessed portion 1 a onthe surface of the lower conductive layer 1.

Then, as shown in FIG. 24, with the photoresist 20 being employed as amask, the underlying layer for vertical bias layer 2 a and the verticalbias layer 2 b are deposited so as to partially fill in the recessedportion 1 a of the lower conductive layer 1, and then the photoresist 20is removed.

Then, as shown in FIG. 25, on top of the lower conductive layer 1 andthe vertical bias layer 2 b, formed and layered in the following orderare the underlying layer for free layer 3 a, the free layer 3 b, thenon-magnetic layer 4, the fixed layer 5, the fixing layer 6 b, and theupper layer 7.

Then, as shown in FIG. 26, the photoresist 21 is provided to cover thecentral portion of the region having no vertical bias layer 2 b arrangedimmediately below the upper surface of the upper layer 7. With thephotoresist 21 being employed as a mask, the non-magnetic layer 4, thefixed layer 5, the fixing layer 6 b, and the upper layer 7 are patternedby dry etching or like means. Then, the periphery of the non-magneticlayer 4, the fixed layer 5, the fixing layer 6 b, and the upper layer 7is buried in the insulation layer 11.

Then, as shown in FIG. 27, the photoresist 21 is removed to form thephotoresist 22, patterned to cover a region broader than that covered bythe photoresist 21, at a position on the upper layer 7 and theinsulation layer 11 where the photoresist 21 has once been formed. Withthe photoresist 22 being employed as a mask, the underlying layer forfree layer 3 a, the free layer 3 b, and the insulation layer 11 areetched by dry etching or like means and thereby patterned. Subsequently,this etched region is buried in the insulation layer 11 b to therebyform a magneto-resistance effect element 32 b.

Then, as shown in FIG. 28, the photoresist 22 is removed. Thereafter,the upper conductive layer 15 is deposited on top of the upper layer 7,the insulation layer 11, and the insulation layer 11 b to form aphotoresist (not shown), which is in turn employed to pattern the upperconductive layer 15 by dry etching or like means. Then, this photoresistis removed and the upper shield layer 17 is formed thereupon to form amagneto-resistance effect head 62 b.

The magneto-resistance effect head 62 b formed according to thisembodiment has the same structure and operation as those of themagneto-resistance effect head 62 a according to the second embodimentexcept that the insulation layers 11 and 11 b are formed through twosteps.

Now, a magneto-resistance effect head according to a fourth embodimentof the present invention and the method for fabricating the head aredescribed below. FIGS. 29-34 are fragmentary sectional viewsillustrating the steps of the method for fabricating themagneto-resistance effect head according to this embodiment in the orderin which they appear.

First, by the steps shown in FIGS. 4-6 in the first embodiment, alayered body as shown in FIG. 6 is formed.

Then, as shown in FIG. 29, on top of the lower conductive layer 1 andthe vertical bias layer 2 b, the following layers are formed andlayered. That is, an underlying layer for magnetic layer 8 a, a magneticlayer 8 b, a second non-magnetic layer 9, the free layer 3 b, the firstnon-magnetic layer 4, the fixed layer 5, the fixing layer 6 b, and theupper layer 7 are formed and layered in that order.

Then, as shown in FIG. 30, the photoresist 21 is formed so as topartially cover the region having no vertical bias layer 2 b arrangedimmediately below the upper surface of the upper layer 7. Then, thesecond non-magnetic layer 9, the free layer 3 b, the first non-magneticlayer 4, the fixed layer 5, the fixing layer 6 b, and the upper layer 7are etched by dry etching or the like. Then, the insulation layer 11 isformed to bury the etched portion therein, thus forming amagneto-resistance effect element 33 a on top of the lower shield layer16.

Then, as shown in FIG. 31, the photoresist 21 is removed and the upperconductive layer 15 is deposited on the upper layer 7 and the insulationlayer 11. Then, a photoresist (not shown) is formed to pattern the upperconductive layer 15 by dry etching or the like and thereafter thephotoresist is removed, on which the upper shield layer 17 is formed,thereby forming a magneto-resistance effect head 63 a.

Now, the structure of the magneto-resistance effect head 63 a accordingto this embodiment is described below. As shown in FIG. 31, themagneto-resistance effect head 63 a is characterized in that themagnetic layer 8 b is provided below the free layer 3 b via thenon-magnetic layer 9.

As shown in FIG. 31, the lower shield layer 16 and the lower conductivelayer 1 are provided on the substrate (not shown), the lower conductivelayer 1 has the recessed portion 1 a, and the underlying layer forvertical bias layer 2 a and the vertical bias layer 2 b are provided onthe recessed portion 1 a. On top of the portion having no underlyinglayer for vertical bias layer 2 a and no vertical bias layer 2 b on thelower conductive layer 1 and on top of the vertical bias layer 2 b,provided are the underlying layer for magnetic layer 8 a and themagnetic layer 8 b. On top of the magnetic layer 8 b, layered in thefollowing order are the second non-magnetic layer 9 that is notpatterned immediately above the vertical bias layer 2 b, the free layer3 b, the first non-magnetic layer 4, the fixed layer 5, the fixing layer6 b, and the upper layer 7.

In addition, the second non-magnetic layer 9, the free layer 3 b, thefirst non-magnetic layer 4, the fixed layer 5, the fixing layer 6 b, andthe upper layer 7 are buried in the insulation layer 11, the uppersurface of upper layer 7 is exposed to the upper surface of theinsulation layer 11. Furthermore, the upper conductive layer 15 ispatterned on the upper layer 7 and the insulation layer 11, and theupper shield layer 17 is provided on the upper conductive layer 15.

In the aforementioned structure, the magnetic layer 8 b is to transmit avertical bias magnetic field applied by the vertical bias layer 2 b tothe free layer 3 b by means of magnetic coupling such as ferromagneticcoupling, antiferromagnetic coupling, or magneto-static coupling. Inaddition, the second non-magnetic layer 9 allows the component materialand the film thickness thereof to control the magnetic coupling betweenthe magnetic layer 8 b and the free layer 3 b. The underlying layer formagnetic layer 8 a is to improve film quality such as thecrystallization properties of the magnetic layer 8 b and provide goodmagnetic properties for the magnetic layer 8 b. Incidentally, thenon-magnetic layer 4 is an insulation layer for conducting a tunnelingcurrent therethrough, whereas the second non-magnetic layer 9 is anelectrically conductive layer for controlling the magnetic couplingbetween the magnetic layer 8 b and the free layer 3 b.

As materials forming the magnetic layer 8 b, employed are alloys such asNiFe, Co, CoFe, NiFeCo, FeCo, CoFeB, CoZrMo, CoZrNb, CoZr, CoZrTa, CoHf,CoTa, CoTaHf, CoNbHf, CoZrNb, CoHfPd, CoTaZrNb, and CoZrMoNi, asingle-layer film of an amorphous magnetic material, a mixture film, ora multi-layered film. In particular, NiFe, Co, CoFe, NiFeCo, or FeCo isfavorable. On the other hand, as an additive element, it is possible touse one or more types of elements selected from the group consisting ofTa, Hf, Zr, W, Cr, Ti, Mo, Pt, Ni, Ir, Cu, Ag, Co, Zn, Ru, Rh, Re, Au,Os, Pd, Nb, and V.

Materials forming the second non-magnetic layer 9 include a singlematerial of one type, a mixture of materials of two or more types, acompound of two or more types, or a multi-layered film formed ofmaterials of two or more types, which are selected from the groupconsisting of Ti, V, Cr, Co, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag,Hf, Ta, W, Re, Os, Ir, Pt, Au, Si, Al, Ti, Ta, Pt, Ni, Co, Re, and V. Inparticular, Ru and Cr are favorable. Materials forming the underlyinglayer for magnetic layer 8 a include a single material of one type, amixture of materials of two or more types, a compound of two or moretypes, or a multi-layered film formed of materials of two or more types,which are selected from the group consisting of Ta, Hf, Zr, W. Cr, Ti,Mo, Pt, Ni, Ir, Cu, Ag, Co, Zn, Ru, Rh, Re, Au, Os, Pd, Nb, and V. Inparticular, Ta and Zr are more favorable.

The component material and the function of other layers of themagneto-resistance effect head 63 a according to this embodiment are thesame as those of each of the layers of the magneto-resistance effecthead 61 a according to the aforementioned first embodiment.

Now, described below is the operation of the magneto-resistance effecthead 63 a. Application of an external magnetic field to themagneto-resistance effect head 63 a will cause a magnetic field to beapplied to the magnetic layer 8 b via the vertical bias layer 2 b. Then,a vertical bias magnetic field is applied by the magnetic layer 8 b viathe second non-magnetic layer 9 to the free layer 3 b by means ofmagnetic coupling such as ferromagnetic coupling, antiferromagneticcoupling, or magneto-static coupling. And, the orientation ofmagnetization of the free layer 3 b changes in accordance with thedirection and the magnitude of this magnetic field. Since theorientation of magnetization of the fixed layer 5 is pinned by thefixing layer 6 b, a change occurs in orientation of magnetizationbetween the fixed layer 5 and the free layer 3 b, causing a change inelectrical resistance of the non-magnetic layer 4. In this state, thelower conductive layer 1 and the upper conductive layer 15 allow a sensecurrent to flow in the direction perpendicular to the non-magnetic layer4 to measure the electrical resistance of the non-magnetic layer 4,thereby making it possible to detect the external magnetic field.

Now, an effect of this embodiment is described below. In themagneto-resistance effect head 63 a according to this embodiment, avertical bias magnetic field is applied to the free layer 3 b from thevertical bias layer 2 b through two steps of process, thereby assuringthe application of the vertical bias magnetic field and facilitating thecontrol of the amount of application of the magnetic field. In addition,as shown in FIG. 31, the free layer 3 b and the fixed layer 5 are notarranged near the vertical bias layer 2 b but only the magnetic layer 8b is disposed near the vertical bias layer 2 b. This allows the verticalbias layer 2 b to apply a magnetic field to the magnetic layer 8 bpositively and effectively, also making it possible to prevent theleakage of sense current from the free layer 3 b or the fixed layer 5 tothe vertical bias layer 2 b.

FIGS. 32 and FIG. 33 are fragmentary sectional views illustrating avariation of the magneto-resistance effect element according to thisembodiment. FIG. 32 illustrates a magneto-resistance effect element 33 bin which the magnetic layer 8 b is patterned so that the end portion ofthe magnetic layer 8 b is in contact with that of the vertical biaslayer 2 b.

In addition, FIG. 33 illustrates a magneto-resistance effect element 33c in which the magnetic layer 8 b is patterned so that the end portionof the magnetic layer 8 b overlaps the vertical bias layer 2 b. Themagneto-resistance effect elements 33 b, 33 c, shown in FIGS. 32 and 33,can constitute the magneto-resistance effect head.

Incidentally, in this embodiment, it has been explained in which thesecond non-magnetic layer 9, the free layer 3 b, and the non-magneticlayer 4 are patterned in conjunction with the fixed layer 5, the fixinglayer 6 b, and the upper layer 7. However, the second non-magnetic layer9, the free layer 3 b, and the non-magnetic layer 4 may be extended asthe magnetic layer 8 b or may be patterned to be larger than the patternof the fixed layer 5, the fixing layer 6 b, and the upper layer 7 andsmaller than the pattern of the magnetic layer 8 b. Furthermore, thepattern of the second non-magnetic layer 9 may be extended further thanthat of the free layer 3 b or the pattern of the free layer 3 b may beextended further than that of the non-magnetic layer 4.

In addition, the underlying layer for vertical bias layer 2 a, theunderlying layer for magnetic layer 8 a, the second non-magnetic layer9, and the upper layer 7 may be omitted, and a protective layer forprotecting the vertical bias layer may be provided on top of thevertical bias layer 2 b.

Furthermore, this embodiment has shown that the lower shield layer 16and the lower conductive layer 1 provided separately. However, like theaforementioned embodiments 1 to 3, the lower shield layer 16 and lowerconductive layer 1 may be a common layer. In this case, the lowerconductive layer 1 is omitted. In addition, the upper shield 17 and theupper conductive layer 15 may be a common layer. In this case, the upperconductive layer 15 is omitted. This allows the gap between the top andbottom shield layers to be made smaller. Furthermore, an upper gapinsulation layer may be provided between the upper conductive layer 15and the shield layer 17 or a lower gap insulation layer may be providedbetween the lower shield layer 16 and the lower conductive layer 1.

Now, a fifth embodiment according to the present invention is describedbelow. FIGS. 34-37 are fragmentary sectional views illustrating thesteps of a method for fabricating a magneto-resistance effect headaccording to this embodiment in the order in which they appear.

First, a layered body as shown in FIG. 16 is formed through the stepsaccording to the aforementioned second embodiment shown in FIGS. 13-19.

Then, as shown in FIG. 34, the photoresist 21 is removed. Then, on topof the exposed portion of the lower conductive layer 1 and the verticalbias layer 2 b, formed and layered are the following layers. That is,the underlying layer for magnetic layer 8 a, the magnetic layer 8 b, thesecond non-magnetic layer 9, the free layer 3 b, the non-magnetic layer4, the fixed layer 5, the fixing layer 6 b, and the upper layer 7 areformed and layered in that order.

Then, as shown in FIG. 35, the photoresist 22 is provided to cover theregion having no vertical bias layer 2 b arranged immediately below theupper surface of the upper layer 7. With the photoresist 22 beingemployed as a mask, patterned by dry etching or like means are theunderlying layer for magnetic layer 8 a, the magnetic layer 8 b, thesecond non-magnetic layer 9, the free layer 3 b, the non-magnetic layer4, the fixed layer 5, the fixing layer 6 b, and the upper layer 7.

Then, as shown in FIG. 36, the photoresist 22 is removed to form thephotoresist 23 on the upper layer 7 to cover the central portion of theupper layer 7. With the photoresist 23 being employed as a mask,patterned by dry etching or like means are the second non-magnetic layer9, the free layer 3 b, the non-magnetic layer 4, the fixed layer 5, thefixing layer 6 b, and the upper layer 7. Then, the periphery of thepattern of the second non-magnetic layer 9, the free layer 3 b, thenon-magnetic layer 4, the fixed layer 5, the fixing layer 6 b, and theupper layer 7 is buried in the insulation layer 11, thereby forming amagneto-resistance effect element 34 a on top of the lower shield layer16.

Then, as shown in FIG. 37, after the photoresist 23 has been removed,the upper conductive layer 15 is deposited on the upper layer 7 and theinsulation layer 11 to form a photoresist (not shown). Then, the upperconductive layer 15 is patterned by dry etching or like means andthereafter this photoresist is removed, on which the upper shield layer17 is formed, thereby forming a magneto-resistance effect head 64 a.

Now, the structure of the magneto-resistance effect head 64 a accordingto this embodiment is described below. As shown in FIG. 37, themagneto-resistance effect head 64 a according to this embodiment has adifferent shape of the underlying layer for magnetic layer 8 a and themagnetic layer 8 b in comparison with the magneto-resistance effect head63 a according to the fourth embodiment shown in FIG. 31. In thisembodiment, the underlying layer for magnetic layer 8 a and the magneticlayer 8 b are patterned to allow their end portions to be flush with theend portions of the underlying layer for vertical bias layer 2 a and thevertical bias layer 2 b and in contact with each other. In themagneto-resistance effect head 64 a according to this embodiment, thestructural operation and effect thereof are the same as those of themagneto-resistance effect head 63 a according to the aforementionedfourth embodiment except the shape of the underlying layer for magneticlayer 8 a and the magnetic layer 8 b.

Incidentally, in this embodiment, it has been explained in which thenon-magnetic layer 4 is patterned in conjunction with the fixed layer 5,the fixing layer 6 b, and the upper layer 7. However, like theaforementioned fourth embodiment, the non-magnetic layer 4 may beextended as the magnetic layer 8 b or may be patterned to be larger thanthe pattern of the fixed layer 5, the fixing layer 6 b, and the upperlayer 7 and smaller than the pattern of the free layer 3 b.

Furthermore, the pattern of the second non-magnetic layer 9 may beextended further than that of the magnetic layer 8 b or the pattern ofthe magnetic layer 8 b may be extended further than that of thenon-magnetic layer 4.

In addition, in this embodiment, it has been explained in which theupper conductive layer 15 is patterned, however, the upper conductivelayer 15 may not be patterned but extended.

Now, a sixth embodiment according to the present invention is describedbelow. FIGS. 38-42 are fragmentary sectional views illustrating thesteps of a method for fabricating a magneto-resistance effect headaccording to this embodiment in the order in which they appear.

First, a layered body as shown in FIG. 5 is formed through the stepsaccording to the aforementioned first embodiment shown in FIGS. 4 and 5.

Then, as shown in FIG. 38, the photoresist 20 is removed. Then, on thelower conductive layer 1, formed and layered in the following order arethe underlying layer for magnetic layer 8 a, the magnetic layer 8 b, thesecond non-magnetic layer 9, the free layer 3 b, the non-magnetic layer4, the fixed layer 5, the fixing layer 6 b, and the upper layer 7.

Then, as shown in FIG. 39, the photoresist 21 is provided to cover theregion having no recessed portion 1 a of the lower conductive layer 1arranged immediately below the upper surface of the upper layer 7. Withthe photoresist 21 being employed as a mask, the second non-magneticlayer 9, the free layer 3 b, the non-magnetic layer 4, the fixed layer5, the fixing layer 6 b, and the upper layer 7 are patterned. Thisallows the insulation layer 11 to bury therein the periphery of thesecond non-magnetic layer 9, the free layer 3 b, the non-magnetic layer4, the fixed layer 5, the fixing layer 6 b, and the upper layer.

Then, as shown in FIG. 40, the photoresist 21 is removed to form thephotoresist 22 to cover the region having no recessed portion 1 aimmediately below the upper surface of the upper layer 7 and theinsulation layer. And, the region covered with the photoresist 21 isincluded in the region to be covered by the photoresist 22.

Then, as shown in FIG. 41, with the photoresist 22 being employed as amask, the insulation layer 11, the underlying layer for magnetic layer 8a, and the magnetic layer 8 b are patterned by etching. Subsequently,the Underlying layer vertical bias 2 a and the vertical bias layer 2 bare formed successively, a second insulation layer 11 b is formed on thevertical bias layer 2 b, and a magneto-resistance effect element 34 b isformed on the lower conductive layer 16.

Then, as shown in FIG. 41, the photoresist 22 is removed. Thereafter, onthe upper layer 7, the insulation layer 11, and the second insulationlayer 11 b, the upper conductive layer 15 is deposited to form aphotoresist (not shown). After the upper conductive layer 15 has beenpatterned by dry etching or like means, the photoresist is removed andthe upper shield layer 17 is formed thereupon to form themagneto-resistance effect head 64 b.

The magneto-resistance effect head 64 b formed according to thisembodiment has the same structure and operation as those of themagneto-resistance effect head 64 a according to the fifth embodimentexcept that the insulation layers 11 and 11 b are formed through twosteps.

Now, described below is a seventh embodiment according to the presentinvention. FIGS. 43-49 are fragmentary sectional views illustrating thesteps of a method for fabricating a magneto-resistance effect headaccording to this embodiment in the order in which they appear.

First, as shown in FIG. 43, the lower shield layer 16 and the lowerconductive layer 1 are successively formed on top of a substrate (notshown).

Then, as shown in FIG. 44, formed and layered in the following order arethe underlying layer for fixing layer 6 a, the fixing layer 6 b, thefixed layer 5, the first non-magnetic layer 4, the free layer 3 b, andthe second non-magnetic layer 9.

Then, as shown in FIG. 45, the photoresist 20 is patterned on the secondnon-magnetic layer 9. Then, the underlying layer for fixing layer 6 a,the fixing layer 6 b, the fixed layer 5, the first non-magnetic layer 4,the free layer 3 b, and the second non-magnetic layer 9 are patterned bydry etching or like means. A pattern 29 a is thereby formed whichcomprises the underlying layer for fixing layer 6 a, the fixing layer 6b, the fixed layer 5, the first non-magnetic layer 4, the free layer 3b, and the second non-magnetic layer 9, which have been patterned.

Then, as shown in FIG. 46, the insulation layer 11 is formed to bury thepattern 29 a therein. The insulation layer 11 is made equal in height tothe pattern 29 a near the pattern 29 a but is slightly lower than thepattern 29 a at a given distance from the pattern 29 a, between which asmooth slope connects.

Then, as shown in FIG. 47, on the insulation layer 11, formed are theunderlying layer for vertical bias layer 2 a and the vertical bias layer2 b. And, the vertical bias layer 2 b is varied in thickness along theslope of the insulation layer 11, allowing the vertical bias layer 2 bto be thick in thickness at a given distance from the pattern 29 a andreduced in thickness with increasing proximity to the pattern 29 a.

Then, as shown in FIG. 48, the photoresist 20 is removed to form themagnetic layer 8 b and the upper layer 7 on the vertical bias layer 2 b,thereby forming a magneto-resistance effect element 35 a.

Then, as shown in FIG. 49, the upper conductive layer 15 is deposited onthe upper layer 7 and the photoresist (not shown) is formed. After theupper conductive layer 15 has been patterned by dry etching or likemeans, the photoresist is removed to form the upper shield layer 17thereupon, thus forming a magneto-resistance effect head 65 a.

Now, the structure of the magneto-resistance effect head 65 a accordingto this embodiment is described below. As shown in FIG. 49, the lowershield layer 16 is provided and the lower conductive layer 1 is providedon the lower shield layer 16. On top of the lower conductive layer 1,formed is the pattern 29 a made up of the underlying layer for fixinglayer 6 a, the fixing layer 6 b, the fixed layer 5, the firstnon-magnetic layer 4, the free layer 3 b, and the second non-magneticlayer 9, which have been patterned. The insulation layer 11 is arrangedon the periphery of the pattern 29 a, and the pattern 29 a is buried inthe insulation layer 11.

The upper surface of the insulation layer 11 is flush with that of thepattern 29 a near the pattern 29 a but is slightly lower than the uppersurface of the pattern 29 a at a given distance from the pattern 29 a,between which a smooth slope connects. The vertical bias layer 2 b isprovided on the insulation layer 11 along the topography of the uppersurface of the insulation layer 11 in a manner such that at least partof the vertical bias layer 2 b in the direction of its thickness isburied in the insulation layer 11. And, the vertical bias layer 2 b isthick in thickness at a given distance from the pattern 29 a and reducedin thickness with increasing proximity to the pattern 29 a. On thevertical bias layer 2 b and the pattern 29 a, provided are the magneticlayer 8 and the upper layer 7.

On the upper layer 7, provided is the upper conductive layer 15, on topof which provided is the upper shield layer 17.

Now, the operation of the magneto-resistance effect head 65 a accordingto this embodiment is described below. Application of an externalmagnetic field to the magneto-resistance effect head 65 a will cause themagnetic field to be applied to the magnetic layer 8 b via the verticalbias layer 2 b. Subsequently, a vertical bias magnetic field is appliedfrom the magnetic layer 8 b to the free layer 3 b via the secondnon-magnetic layer 9 by means of a magnetic coupling such asferromagnetic coupling, anti-ferromagnetic coupling, or magneto-staticcoupling. And, the orientation of magnetization of the free layer 3 bchanges in accordance with the direction and magnitude of this magneticfield. Since the orientation of magnetization of the fixed layer 5 ispinned by the fixing layer 6 b, a change occurs in orientation ofmagnetization between the fixed layer 5 and the free layer 3 b, causinga change in electrical resistance of the non-magnetic layer 4. In thisstate, the lower conductive layer 1 and the upper conductive layer 15allow a sense current to flow in the direction perpendicular to thenon-magnetic layer 4 to measure the electrical resistance of thenon-magnetic layer 4, thereby making it possible to detect the externalmagnetic field.

Now, an effect of this embodiment is described below. In themagneto-resistance effect head 65 a according to this embodiment, avertical bias magnetic field is applied to the free layer 3 b from thevertical bias layer 2 b through two steps of process, thereby assuringthe application of the vertical bias magnetic field and facilitating thecontrol of the amount of application of the magnetic field.

Incidentally, in this embodiment, it has been explained in which theunderlying layer for fixing layer 6 a, the fixing layer 6 b, the fixedlayer 5, the first non-magnetic layer 4, the free layer 3 b, and thesecond non-magnetic layer 9 are patterned in the same way. However, itis necessary to pattern at least the free layer 3 b but not necessary topattern the underlying layer for fixing layer 6 a, the fixing layer 6 b,the fixed layer 5, and the first non-magnetic layer 4. In addition, thepattern of the underlying layer for fixing layer 6 a may be extendedfurther than that of the fixing layer 6 b. The pattern of the fixinglayer 6 b may be extended further than that of the fixed layer 5. Thepattern of the fixed layer 5 may be extended further than that of thenon-magnetic layer 4. The pattern of the non-magnetic layer 4 may beextended further than that of the free layer 3 b. Furthermore, thisembodiment has shown that the upper surface of the insulation layer 11is lower than that of the pattern of the free layer 3 b. However, theupper surface of the insulation layer 11 may be equal in height to theupper surface of the pattern of the free layer 3 b and higher than theupper surface of the pattern of the free layer 3 b.

FIGS. 50-54 are fragmentary sectional views illustrating the structureof a magneto-resistance effect element according to a variation of thisembodiment. A magneto-resistance effect element 35 b shown in FIG. 50 isdifferent from the magneto-resistance effect element 35 a shown in FIG.49 in that the underlying layer for fixing layer 6 a, the fixing layer 6b, the fixed layer 5, and the first non-magnetic layer 4 are notpatterned. On the first non-magnetic layer 4, provided are the freelayer 3 b and the second non-magnetic layer 9, and these patterns areburied in the insulation layer 11. The magneto-resistance effect element35 b has the same structure as that of the magneto-resistance effectelement 35 a except the topography of the underlying layer for fixinglayer 6 a, the fixing layer 6 b, the fixed layer 5, and the firstnon-magnetic layer 4. The operation of the magneto-resistance effectelement 35 b is also the same as that of the magneto-resistance effectelement 35 a.

In comparison with the magneto-resistance effect element 35 a, themagneto-resistance effect element 35 b is advantageous in that theetching process for the underlying layer for fixing layer 6 a, thefixing layer 6 b, the fixed layer 5, and the first non-magnetic layer 4can be omitted upon fabrication.

This variation has shown that the free layer 3 b and the secondnon-magnetic layer 9 are patterned by etching of the first non-magneticlayer 4 using the photoresist as a mask. However, it is necessary topattern at least the free layer 3 b, and it can be selected asappropriate which layers to pattern in the layered body made up of theunderlying layer for fixing layer 6 a, the fixing layer 6 b, the fixedlayer 5, and the first non-magnetic layer.

On the other hand, in a magneto-resistance effect element 35 c shown inFIG. 51, the first non-magnetic layer 4, the free layer 3 b, and thesecond non-magnetic layer 9 are patterned.

Furthermore, in a magneto-resistance effect element 35 d shown in FIG.52, the fixed layer 5, the first non-magnetic layer 4, the free layer 3b, and the second non-magnetic layer 9 are patterned.

Still furthermore, in a magneto-resistance effect element 35 e shown inFIG. 53, the pattern of the vertical bias layer 2 b is provided apartfrom a pattern 29 b made up of the first non-magnetic layer 4, the freelayer 3 b, and the second non-magnetic layer 9. This makes it possibleto prevent more positively the leakage of sense current to the verticalbias layer 2 b. The structure and operation of the magneto-resistanceeffect element 35 e is the same as those of the magneto-resistanceeffect element 35 c shown in FIG. 51 except those mentioned in theforegoing.

This variation has shown that the free layer 3 b and the secondnon-magnetic layer 9 are patterned. However, it is necessary to patternat least the free layer 3 b, but it can be selected as appropriate whichlayers to pattern in the layered body made up of the underlying layerfor fixing layer 6 a, the fixing layer 6 b, the fixed layer 5, and thefirst non-magnetic layer.

In addition, this variation has shown that the upper surface of theinsulation layer 11 is higher than that of the pattern of the free layer3 b. However, the upper surface of the insulation layer 11 may begenerally equal in height to the upper surface of the pattern of thefree layer 3 b or lower than the upper surface of the pattern of thefree layer 3 b.

Furthermore, this variation has shown that the magnetic layer 8 b is notpatterned. However, at least part of the magnetic layer 8 b is locatednear the vertical bias layer 2 b just to allow a vertical bias magneticfield to be applied to the vertical bias layer 2 b from the verticalbias layer 2 b.

In a magneto-resistance effect element 35 f shown in FIG. 54, the endportion of the pattern of the magnetic layer 8 b sits on part of thevertical bias layer 2 b.

In a magneto-resistance effect element 35 g shown in FIG. 55, the endportion of the pattern of the magnetic layer 8 b is in contact with thatof the vertical bias layer 2 b.

This variation has shown that the free layer 3 b and the secondnon-magnetic layer 9 are patterned in the same way. However, like amagneto-resistance effect element 35 h shown in FIG. 56, the secondnon-magnetic layer 9 may be extended over the vertical bias layer 2 b.

In addition, like a magneto-resistance effect element 35 i shown in FIG.57, the second non-magnetic layer 9 may be extended over the insulationlayer 11.

The magneto-resistance effect elements 35 b, 35 c, 35 d, 35 e, 35 f, 35g, 35 h, and 35 i, shown in FIGS. 50-57, can also be employed for themagneto-resistance effect head in the same way as the magneto-resistanceeffect element 35 a.

Incidentally, in this embodiment, the lower shield layer 16 and thelower conductive layer 1 may be the same layer, and the upper shieldlayer 17 and the upper conductive layer 15 may be the same layer. Inaddition, an upper gap layer may be provided between the upperconductive layer 15 and the shield layer 17, and a lower gap layer maybe provided between the lower shield layer 16 and the lower conductivelayer 1.

In addition, the underlying layer for vertical bias layer 2 a, theunderlying layer for fixing layer 6 a, the second non-magnetic layer 9,and the upper layer 7 may be omitted, and a protective layer forprotecting the vertical bias layers may be provided on the vertical biaslayer 2 b.

Now, an eighth embodiment according to the present invention isdescribed below. FIGS. 58-64 are fragmentary sectional viewsillustrating the steps of a method for fabricating a magneto-resistanceeffect head according to this embodiment in the order in which theyappear.

First, as shown in FIG. 58, the lower shield layer 16 and the lowerconductive layer 1 are successively formed on a substrate (not shown).

Then, as shown in FIG. 59, formed and layered in the following order arethe underlying layer for fixing layer 6 a, the fixing layer 6 b, thefixed layer 5, the first non-magnetic layer 4, the free layer 3 b, andthe second non-magnetic layer.

Then, as shown in FIG. 60, the photoresist 20 having the opening portion20 a is formed on top of the second non-magnetic layer 9. Then,patterned are the underlying layer for fixing layer 6 a, the fixinglayer 6 b, the fixed layer 5, the first non-magnetic layer 4, the freelayer 3 b, and the second non-magnetic layer 9 by dry etching or likemeans. Thus, a pattern 29 c is formed which is made up of the patternedthe underlying layer for fixing layer 6 a, the fixing layer 6 b, thefixed layer 5, the first non-magnetic layer 4, the free layer 3 b, andthe second non-magnetic layer 9, which have been patterned.

Then, as shown in FIG. 61, the insulation layer 11 is formed to bury thepattern 29 c.

Then, as shown in FIG. 62, on the pattern 29 c and the insulation layer11, formed are the first magnetic layer 8 b, the third non-magneticlayer 13, the second magnetic layer 12, and the vertical bias layer 2 b.

Then, as shown in FIG. 63, the photoresist 21 having the opening portion21 a is formed immediately above the patterned non-magnetic layer 9.Then, with the photoresist 21 being employed as a mask, the verticalbias layer 2 b is patterned, thereby forming a magneto-resistance effectelement 36 a.

Then, as shown in FIG. 64, the photoresist 21 is removed. Then, theupper conductive layer 15 is deposited on the exposed portion of thesecond magnetic layer 12 and the pattern of the vertical bias layer 2 b,and a photoresist (not shown) is formed to perform patterning by dryetching or like means. Thereafter, the photoresist is removed and theupper shield layer 17 is formed thereupon, thereby forming amagneto-resistance effect head 66 a.

Now, the structure of the magneto-resistance effect head 66 a accordingto this embodiment is described below. As shown in FIG. 64, themagneto-resistance effect head 66 a is provided with the lower shieldlayer 16, and the lower conductive layer 1 is provided on top of thelower shield layer 16. Thus, on top of the lower conductive layer 1,formed is the pattern 29 c made up of the underlying layer for fixinglayer 6 a, the fixing layer 6 b, the fixed layer 5, the firstnon-magnetic layer 4, the free layer 3 b, and the second non-magneticlayer 9, which have been patterned. The insulation layer 11 is arrangedaround the pattern 29 c, and the pattern 29 c is buried in theinsulation layer 11.

On the pattern 29 c and the insulation layer 11, provided are the firstmagnetic layer 8 b, a third non-magnetic layer 13, and a second magneticlayer 12. On top of the second magnetic layer 12, the vertical biaslayer 2 b is provided so as not to be disposed immediately above thepattern 29 c.

In addition, the third non-magnetic layer 13 allows the componentmaterial and the film thickness thereof to control the magnetic couplingbetween the second magnetic layer 12 and the magnetic layer 8 b.Materials forming the third non-magnetic layer 13 include a singlematerial of one type, a mixture of materials of two or more types, acompound of two or more types, or a multi-layered film formed ofmaterials of two or more types, which are selected from the groupconsisting of Ti, V, Cr, Co, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag,Hf, Ta, W, Re, Os, Ir, Pt, Au, Si, Al, Ta, Pt, and Ni. In particular, Ruand Cr are favorable.

On the other hand, materials forming the second magnetic layer 12include a single material of one type, a mixture of materials of two ormore types, or a multi-layered film formed of materials of two or moretypes, which are selected from the group consisting of alloys oramorphous magnetic materials such as NiFe, Co, CoFe, NiFeCo, FeCo,CoFeB, CoZrMo, CoZrNb, CoZr, CoZrTa, CoHf, CoTa, CoTaHf, CoNbHf, CoZrNb,CoHfPd, CoTaZrNb, and CoZrMoNi. In particular, NiFe, Co, CoFe, NiFeCo,and FeCo are favorable. In addition, as an additive element, one or moretypes of elements can be used which are selected from the groupconsisting of Ta, Hf, Zr, W, Cr, Ti, Mo, Pt, Ni, Ir, Cu, Ag, Co, Zn, Ru,Rh, Re, Au, Os, Pd, Nb, and V.

Now, the operation of the magneto-resistance effect head 66 a accordingto this embodiment is described below. When an external magnetic fieldis applied to the magneto-resistance effect head 66 a, the magneticfield is applied to the second magnetic layer 12 via the vertical biaslayer 2 b. Subsequently, a vertical bias magnetic field is applied fromthe second magnetic layer 12 to the magnetic layer 8 b via the thirdnon-magnetic layer 13 by means of magnetic coupling such asferromagnetic coupling, anti-ferromagnetic coupling, or magneto-staticcoupling. Furthermore, the vertical bias magnetic field is applied fromthe magnetic layer 8 b to the free layer 3 b via the second non-magneticlayer 9 by means of magnetic coupling such as ferromagnetic coupling,anti-ferromagnetic coupling, or magneto-static coupling.

The orientation of magnetization of the free layer 3 b changes inaccordance with the direction and magnitude of this magnetic field.Since the orientation of magnetization of the fixed layer 5 is pinned bythe fixing layer 6 b, a change occurs in orientation of magnetizationbetween the fixed layer 5 and the free layer 3 b, causing a change inelectrical resistance of the non-magnetic layer 4. In this state, thelower conductive layer 1 and the upper conductive layer 15 allow a sensecurrent to flow in the direction perpendicular to the non-magnetic layer4 to measure the electrical resistance of the non-magnetic layer 4,thereby making it possible to detect the external magnetic field.

Now, an effect of this embodiment is described below. In themagneto-resistance effect head 65 a according to this embodiment, avertical bias magnetic field is applied to the free layer 3 b from thevertical bias layer 2 b through three steps of process, thereby assuringthe application of the vertical bias magnetic field and facilitating thecontrol of the amount of application of the magnetic field.

Another advantage of the magneto-resistance effect head 65 a is providedwhen the layered film made up of the magnetic layer 8 b, the thirdnon-magnetic layer 13, and the second magnetic layer 12 produces astrong anti-ferromagnetic coupling between the magnetic layer 8 b andthe second magnetic layer 12. The advantage is also provided when themagnetization of the magnetic layer 8 (the product of the saturationmagnetization and the film thickness) is made substantially equal tothat of the second magnetic layer 12. In this case, the foregoinglayered film is turned to a merged film having effectively nomagnetization, thus providing no sensitivity to the magnetic field of anexternal magnetic field applied. For this reason, in this case, only thefree layer 3 b, in the structure of FIG. 64, has sensitivity to anexternal magnetic field. Thus, the width of the tracks is determinedonly by the pattern width of the free layer 3 b when themagneto-resistance effect head 65 a functions as the read head. This isadvantageous in making a narrow-track head. Incidentally, even in thiscase, a vertical bias magnetic field is applied precisely to the freelayer 3 b through the aforementioned process. In addition, that themagnetization of the magnetic layer 8 b is substantially equal to thatof the second magnetic layer 12 means that they are equal to each otherto the degree that the aforementioned effect is recognized.

Incidentally, in this embodiment, the underlying layer for fixing layer6 a, the second non-magnetic layer 9, the third non-magnetic layer 13,and the upper layer 7 may be omitted. In addition, an underlying layerfor vertical bias layer may be provided on the lower portion of thevertical bias layer 2 b. In some cases, a protective layer forprotecting a vertical bias layer is provided on the vertical bias layer2 b, and an upper layer is provided on the second magnetic layer 12.

Furthermore, in this embodiment, it has been explained in which theunderlying layer for fixing layer 6 a, the fixing layer 6 b, the fixedlayer 5, the first non-magnetic layer 4, the free layer 3 b, and thesecond non-magnetic layer 9 are patterned in the same way. However, itis necessary to pattern at least the free layer 3 b but not necessary topattern the layered film made up of the underlying layer for fixinglayer 6 a, the fixing layer 6 b, the fixed layer 5, and the firstnon-magnetic layer 4. In addition, the pattern of the underlying layerfor fixing layer 6 a may be extended further than that of the fixinglayer 6 b. The pattern of the fixing layer 6 b may be extended furtherthan that of the fixed layer 5. The pattern of the fixed layer 5 may beextended further than that of the non-magnetic layer 4. The pattern ofthe non-magnetic layer 4 may be extended further than that of the freelayer 3 b. In addition, this embodiment has shown such that the uppersurface of the insulation layer 11 is equal in height to that of thepattern of the free layer 3 b. However, the upper surface of theinsulation layer 11 may be lower than that of the pattern of the freelayer 3 b or higher than the upper surface of the pattern of the freelayer 3 b. Furthermore, FIG. 64 has shown that the second non-magneticlayer 9 and the free layer 3 b are patterned in the same way. However,the pattern of the second non-magnetic layer 9 may be extended furtherthan that of the free layer 3 b.

FIGS. 65-66 are fragmentary sectional views illustrating the structureof a magneto-resistance effect element according to a variation of thisembodiment. With reference to FIG. 64, it has been shown in which thefirst magnetic layer 8 b, the third non-magnetic layer 13, and thesecond magnetic layer 12 are not patterned. However, in amagneto-resistance effect element 36 b shown in FIG. 65, the endportions of patterns of the magnetic layer 8 b, the third non-magneticlayer 13, and the second magnetic layer 12 are arranged under thepattern of the vertical bias layer 2 b.

In addition, in the magneto-resistance effect element 36 c shown in FIG.66, the end portions of patterns of the magnetic layer 8, the thirdnon-magnetic layer 13, and the second magnetic layer 12 are in contactwith the end portions of the pattern of the vertical bias layer 2 b.Incidentally, the magneto-resistance effect elements 36 b and 36 c canalso be employed for the magneto-resistance effect head, like themagneto-resistance effect element 36 a.

Now, a ninth embodiment of the present invention is described below.FIGS. 67-70 are fragmentary sectional views illustrating the steps of amethod for fabricating a magneto-resistance effect head according tothis embodiment in the order in which they appear.

First, a structure body as shown in FIG. 61 is formed through the steps,shown in FIGS. 58-61, according to the aforementioned eighth embodiment.

Then, as shown in FIG. 67, the photoresist 20 is removed, and thephotoresist 21 is formed to cover the peripheral region of the secondnon-magnetic layer 9 and the second non-magnetic layer 9 in theinsulation layer 11.

Then, as shown in FIG. 68, with the photoresist 21 being employed as amask, a recessed portion 11 a is formed in the insulation layer 11, andthe underlying layer for vertical bias layer 2 a and the vertical biaslayer 2 b are formed so as to be buried in the recessed portion 11 a.

Then, as shown in FIG. 69, the photoresist 21 is removed to form thefirst magnetic layer 8 b, the third non-magnetic layer 13, and thesecond magnetic layer 12 in that order, thereby forming amagneto-resistance effect element 37 a.

Then, as shown in FIG. 70, the upper conductive layer 15 is deposited onthe second magnetic layer 12 and then a photoresist (not shown) isformed. With this photoresist being employed as a mask, the upperconductive layer 15 is patterned by dry etching or like means.Thereafter, the photoresist is removed and the upper shield layer 17 isformed thereupon, thereby forming a magneto-resistance effect head 67 a.

Now, the structure of the magneto-resistance effect head 67 a accordingto this embodiment is described below. The magneto-resistance effecthead 67 a is provided with the lower shield layer 16, and the lowerconductive layer 1 is provided on the lower shield layer 16. Then,formed on top of the lower conductive layer 1 is the pattern in whichthe underlying layer for fixing layer 6 a patterned on the fixing layer6 b, the fixed layer 5, non-magnetic layer 4, the free layer 3 b, andthe second non-magnetic layer 9 are layered in that order, and thispattern is buried in the insulation layer 11. As shown in FIG. 70, theinsulation layer 11 has the recessed portion 11 a on the upper surfacethereof, and the underlying layer for vertical bias layer 2 a and thevertical bias layer 2 b are formed so as to be buried in the recessedportion 11 a. Then, on the second non-magnetic layer 9, the insulationlayer 11, and the vertical bias layer 2 b, formed are the magnetic layer8 b, the third non-magnetic layer 13, and the second magnetic layer 12.Furthermore, the patterned upper conductive layer 15 is provided on thesecond magnetic layer 12, and the upper shield layer 17 is provided onthe pattern of the second magnetic layer 12 and the upper conductivelayer 15.

Now, a tenth embodiment according to the present invention is describedbelow. FIGS. 71-76 are fragmentary sectional views illustrating thesteps of a method for fabricating a magneto-resistance effect headaccording to this embodiment in the order in which they appear.

First, as shown in FIG. 71, on a substrate (not shown), formed are thelower shield layer 16 and the lower conductive layer 1.

Then, as shown in FIG. 72, the following layers are formed and layeredon the lower conductive layer 1. That is, the underlying layer forfixing layer 6 a, the fixing layer 6 b, the fixed layer 5, the firstnon-magnetic layer 4, the free layer 3 b, the second non-magnetic layer9, the first magnetic layer 8 b, the third non-magnetic layer 13, thesecond magnetic layer 12, the underlying layer for vertical bias layer 2a, and the vertical bias layer 2 b are formed and layered in that order.

Then, as shown in FIG. 73, the photoresist 20 is patterned on thevertical bias layer 2 b.

Then, as shown in FIG. 74, with the photoresist 20 being employed as amask, etched by dry etching or like means and thereby patterned are theunderlying layer for fixing layer 6 a, the fixing layer 6 b, the fixedlayer 5, the non-magnetic layer 4, the free layer 3 b, the secondnon-magnetic layer 9, the magnetic layer 8 b, the third non-magneticlayer 13, the second magnetic layer 12, the underlying layer forvertical bias layer 2 a, and the vertical bias layer 2 b. Thus, apattern 29 d is formed which is made up of the underlying layer forfixing layer 6 a, the fixing layer 6 b, the fixed layer 5, thenon-magnetic layer 4, the free layer 3 b, the second non-magnetic layer9, the magnetic layer 8 b, the third non-magnetic layer 13, the secondmagnetic layer 12, the underlying layer for vertical bias layer 2 a, andthe vertical bias layer 2 b.

Then, as shown in FIG. 75, the insulation layer 11 is formed to bury thepattern 29 d therein, thereby forming the magneto-resistance effectelement 38 a.

Then, as shown in FIG. 76, the photoresist 20 is removed, and the upperconductive layer 15 is formed on the vertical bias layer 12 and theinsulation layer 11 to form a photoresist (not shown). Then, with thisphotoresist being employed as a mask, the upper conductive layer 15 ispatterned by dry etching or like means. Then, the photoresist is removedto form the upper shield layer 17 thereupon, thus forming amagneto-resistance effect head.

Now, the structure of the magneto-resistance effect head according tothis embodiment is described below. As shown in FIG. 76, themagneto-resistance effect head is provided with a lower shield layer(not shown), and the lower conductive layer 1 is provided on a lowershield layer. On top of the lower conductive layer 1, provided is thepattern 29 d made up of the underlying layer for fixing layer 6 a, thefixing layer 6 b, the fixed layer 5, non-magnetic layer 4, the freelayer 3 b, the second non-magnetic layer 9, the first magnetic layer 8,the third non-magnetic layer 13, the second magnetic layer 12, theunderlying layer for vertical bias layer 2 a, and the vertical biaslayer 2 b, which have been patterned. The pattern 29 d is buried in theinsulation layer 11, and the vertical bias layer 2 b of the pattern 29 dis exposed on the upper surface of the insulation layer 11. In addition,the upper conductive layer 15, which has been patterned, is provided ontop of the pattern 29 d and the insulation layer 11, and the uppershield layer 17 is provided on the upper conductive layer 15 and theinsulation layer 11. Now, the operation of the magneto-resistance effecthead according to this embodiment is described below. The magnetic fieldapplied to the magneto-resistance effect head is applied to the secondmagnetic layer 12 via the vertical bias layer 2 b. Then, the verticalbias magnetic field is applied to the first magnetic layer 8 from thesecond magnetic layer 12 via the third non-magnetic layer 13 by means ofmagnetic coupling such as ferromagnetic coupling, antiferromagneticcoupling, or magneto-static coupling. Furthermore, the vertical biasmagnetic field is applied to the free layer 3 b from the first magneticlayer 8 via the second non-magnetic layer 9 by means of magneticcoupling such as ferromagnetic coupling, antiferromagnetic coupling, ormagneto-static coupling.

The third non-magnetic layer 13 allows the component material and thefilm thickness thereof to control the magnetic coupling between thesecond magnetic layer 12 and the magnetic layer 8. In addition, thesecond non-magnetic layer 9 allows the component material and the filmthickness thereof to control the magnetic coupling between the magneticlayer 8 and the free layer 3 b. As described above, a vertical biasmagnetic field is applied to the free layer 3 b from the vertical biaslayer 2 b through three steps of process, thereby assuring theapplication of the vertical bias magnetic field and facilitating thecontrol of the magnetic field applied.

Incidentally, the underlying layer for fixing layer 6 a, the secondnon-magnetic layer 9, the third non-magnetic layer 13, and theunderlying layer for vertical bias layer 2 a can be omitted.Incidentally, a protective layer for protecting the vertical bias layer2 b may be provided on the vertical bias layer 2 b, while an upper layermay be provided on the second magnetic layer 12.

FIG. 77 is a fragmentary sectional view illustrating the structure of amagneto-resistance effect element 38 b according to a variation of thisembodiment. The magneto-resistance effect element 38 b is provided withthe lower conductive layer 1 on a substrate (not shown). On top of thelower conductive layer 1, provided are the underlying layer for fixinglayer 6 a, the fixing layer 6 b, the fixed layer 5, non-magnetic layer4, the free layer 3 b, the second non-magnetic layer 9, the firstmagnetic layer 8 b, the underlying layer for vertical bias layer 2 a,and the vertical bias layer 2 b. And, these layers have been patternedand buried in the insulation layer 11. The vertical bias layer 2 b isexposed on the upper surface of the insulation layer 11.

First, the vertical bias magnetic field applied to themagneto-resistance effect element 38 b is applied to the magnetic layer8 via the vertical bias layer 2 b. Then, the vertical bias magneticfield is applied to the free layer 3 b from the first magnetic layer 8via the second non-magnetic layer 9 by means of magnetic coupling suchas ferromagnetic coupling, antiferromagnetic coupling, or magneto-staticcoupling. And, the second non-magnetic layer 9 allows the componentmaterial and the film thickness thereof to control the magnetic couplingbetween the magnetic layer 8 and the free layer 3 b.

As described above, a vertical bias magnetic field is applied to thefree layer 3 b from the vertical bias layer 2 b through two steps ofprocess, thereby assuring the application of the vertical bias magneticfield and facilitating the control of the amount of the magnetic fieldapplied.

Incidentally, in this embodiment, it has been explained in which theunderlying layer for fixing layer 6 a, the fixing layer 6 b, the fixedlayer 5, the non-magnetic layer 4, the free layer 3 b, and the secondnon-magnetic layer 9 are patterned in the same way. However, it isnecessary to pattern at least the free layer 3 b but not necessary topattern the layered film made up of the underlying layer for fixinglayer 6 a, the fixing layer 6 b, the fixed layer 5, and the non-magneticlayer 4. In addition, the pattern of the underlying layer for fixinglayer 6 a may be extended further than that of the fixing layer 6 b. Thepattern of the fixing layer 6 b may be extended further than that of thefixed layer 5. The pattern of the fixed layer 5 may be extended furtherthan that of the non-magnetic layer 4. The pattern of the firstnon-magnetic layer 4 may be extended further than that of the free layer3 b.

Now, an eleventh embodiment according to the present invention isdescribed below. FIGS. 78-87 are fragmentary sectional viewsillustrating the steps of a method for fabricating a magneto-resistanceeffect head according to this embodiment in the order in which theyappear.

First, as shown in FIG. 78, the lower shield layer 16 and the lowerconductive layer 1 are successively formed on top of a substrate (notshown).

Then, as shown in FIG. 79, the underlying layer for fixing layer 6 a,the fixing layer 6 b, the fixed layer 5, the first non-magnetic layer 4,the free layer 3 b, and the second non-magnetic layer 9 are formed andlayered in that order on the lower conductive layer 1.

Then, as shown in FIG. 80, the photoresist 20 is patterned on the secondnon-magnetic layer 9. Then, the underlying layer for fixing layer 6 a,the fixing layer 6 b, the fixed layer 5, the first non-magnetic layer 4,the free layer 3 b, and the second non-magnetic layer 9 are patterned bydry etching or like means, thereby forming a pattern 29 e made up ofthese layers.

Then, as shown in FIG. 81, the insulation layer 11 is formed around thepattern 29 e to bury the pattern 29 e therein. And, the insulation layer11 is made equal in height to the pattern 29 e near the pattern 29 e butis slightly lower than the pattern 29 e at a given distance from thepattern 29 e, between which a smooth slope connects.

Then, as shown in FIG. 82, on the insulation layer 11, formed are theunderlying layer for vertical bias layer 2 a and the vertical bias layer2 b. The vertical bias layer 2 b is varied in thickness along the slopeof the insulation layer 11, allowing the vertical bias layer 2 b to bethick in thickness at a given distance from the pattern 29 e and reducedin thickness with increasing proximity to the pattern 29 e.

Then, as shown in FIG. 83, the photoresist 20 is removed to form thefirst magnetic layer 8 b and a fourth non-magnetic layer 18 on thesecond non-magnetic layer 9 and the vertical bias layer 2 b.

Then, as shown in FIG. 84, a second free layer 19, a fifth non-magneticlayer 25, a second fixed layer 26, a second fixing layer 27, and theupper layer 7 are formed in that order.

Then, as shown in FIG. 85, the photoresist 21 is formed to cover theregion that matches the pattern 29 e on the upper layer 7. With thephotoresist 21 being employed as a mask, the fourth non-magnetic layer18, the second free layer 19, the fifth non-magnetic layer 20, thesecond fixed layer 26, the second fixing layer 27, and the upper layer 7are patterned. Formed thereby is a pattern 29 f made up of the fourthnon-magnetic layer 18, the second free layer 19, the fifth non-magneticlayer 25, the second fixed layer 26, the second fixing layer 27, and theupper layer 7.

Then, as shown in FIG. 86, around the pattern 29 f, the insulation layer11 b is formed to bury pattern 29 f therein, thereby providing amagneto-resistance effect element 39 a formed on the lower shield layer16.

Then, as shown in FIG. 87, the photoresist 21 is removed, and the upperconductive layer 15 is deposited on the upper layer 7 and the insulationlayer 11 b to form a photoresist (not shown). With this photoresistbeing employed as a mask, the upper conductive layer 15 is patterned bydry etching or like means. Thereafter, the photoresist is removed andthe upper shield layer 17 is formed thereupon, thus forming amagneto-resistance effect head 69 a.

Now, the structure of the magneto-resistance effect element 39 aaccording to this embodiment is described below. As shown in FIG. 87,the magneto-resistance effect element 39 a is adapted that thenon-magnetic layer, the free layer, the non-magnetic layer, the fixedlayer, and the fixing layer are formed to be vertically symmetric withrespect to the first magnetic layer 8 b to which a vertical biasmagnetic field is applied from the underlying layer for vertical biaslayer 2 a.

The magneto-resistance effect element 39 a is provided with the lowershield layer 16, and the lower conductive layer 1 is provided on thelower shield layer 16. On top of the lower conductive layer 1, formed isthe pattern 29 e made up of the underlying layer for fixing layer 6 a,the fixing layer 6 b, the fixed layer 5, the first non-magnetic layer 4,the free layer 3 b, and the second non-magnetic layer 9, which have beenpatterned. The pattern 29 e is buried in the insulation layer 11.

The upper surface of the insulation layer 11 is generally flush withthat of the pattern 29 e near the pattern 29 e but is slightly lowerthan the upper surface of the pattern 29 e at a given distance from thepattern 29 e. The pattern of the underlying layer for vertical biaslayer 2 a and the vertical bias layer 2 b is provided to allow at leastpart thereof in the direction of film thickness to be buried in theinsulation layer 11. The second non-magnetic layer 9 is provided on thepattern 29 e and the vertical bias layer 2 b.

On top of the second non-magnetic layer 9, the pattern 29 f is providedwhich is made up of the fourth non-magnetic layer 18, the second freelayer 19, the fifth non-magnetic layer 25, the second fixed layer 26,the second fixing layer 27, and the upper layer 7, which have beenpatterned, with the pattern 29 f being buried in the insulation layer 11b. In addition, the upper conductive layer 15 and the upper shield layer17 are provided on the pattern 29 f and the insulation layer 11 b.

Now, the operation of the magneto-resistance effect element 39 aaccording to this embodiment is described below. When a sensorcontaining the magneto-resistance effect element 39 a is subjected to anexternal magnetic field, the second free layer 19, like the free layer 3b, serves as a magnetic layer which changes its orientation ofmagnetization in accordance with the orientation and magnitude of themagnetic field. The fifth non-magnetic layer 25 is disposed between thesecond free layer 19 and the second fixed layer 26, and varies inelectrical resistance in accordance with the angle between theorientation of magnetization of the second free layer and that of thesecond fixed layer 26. The orientation of magnetization of the secondfixed layer 26 is pinned by the second fixing layer 27. Thus, a changein orientation of magnetization of the free layer in accordance with theorientation and magnitude of an external magnetic field would cause achange to occur between the orientation of magnetization of the fixedlayer, the orientation of which is pinned, and that of the free layer.This results in a change in resistance of the fifth non-magnetic layer25.

In the magneto-resistance effect element 39 a, the amount of a change inelectrical resistance produced upon conducting a sense current from thelower conductive layer 1 to the upper conductive layer 15 is equal tothe sum of a change in electrical resistance of the pattern 29 e locatedbelow the magnetic layer 8 b and a change in electrical resistance ofthe pattern 29 f located above the magnetic layer 8 b.

Generally, in the magneto-resistance effect element, the free layer isunavoidably subjected to the influence of a circular electric magneticfield caused by a current flowing perpendicularly to the film surface.However, in the magneto-resistance effect element 39 a according to thisembodiment, the influence of the electric magnetic field to which thefree layer 3 b is subjected is opposite to that of the electric magneticfield to which the second free layer 19 is subjected, thereby cancelingout the influences as a whole. Thus, it is made possible tosignificantly reduce the influence of the electric magnetic field.

In addition, in the magneto-resistance effect element 39 a, the verticalbias magnetic field applied is first applied to the first magnetic layer8 b via the vertical bias layer 2 b. Then, the vertical bias magneticfield is applied to the free layer 3 b from the first magnetic layer 8 bvia the second non-magnetic layer 9 and to the second free layer 19through the fourth non-magnetic layer 18. The second non-magnetic layer9 controls the magnetic coupling between the first magnetic layer 8 band the free layer 3 b by the component material and film thicknessthereof, while the fourth non-magnetic layer 18 controls the magneticcoupling between the magnetic layer 8 b and the second free layer 19 bythe component material and film thickness thereof. As described above, avertical bias magnetic field is applied to the free layer 3 b and thesecond free layer 19 from the vertical bias layer 2 b through two stepsof process, thereby assuring the application of the vertical biasmagnetic field and facilitating the control of the amount of applicationof the magnetic field.

Incidentally, in this embodiment, the underlying layer for vertical biaslayer 2 a, the underlying layer for fixing layer 6 a, the secondnon-magnetic layer 9, the fourth non-magnetic layer 18, and the upperlayer 7 can be omitted. Furthermore, in some cases, a protective layerfor protecting the vertical bias layer may be provided on the verticalbias layer 2 b.

In addition, in this embodiment, it has been explained in which theunderlying layer for fixing layer 6 a, the fixing layer 6 b, the fixedlayer 5, the first non-magnetic layer 4, the free layer 3 b, and thesecond non-magnetic layer 9 are patterned in the same way. However, itis necessary to pattern at least the free layer 3 b but not necessary topattern the underlying layer for fixing layer 6 a, the fixing layer 6 b,the fixed layer 5, and the first non-magnetic layer 4. Furthermore, thepattern of the underlying layer for fixing layer 6 a may be extendedfurther than that of the fixing layer 6 b. The pattern of the fixinglayer 6 b may be extended further than that of the fixed layer 5. Thepattern of the fixed layer 5 may be extended further than that of thenon-magnetic layer 4. The pattern of the first non-magnetic layer 4 maybe extended further than that of the free layer 3 b.

Still furthermore, this embodiment has shown that the upper surface ofthe insulation layer 11 is lower than that of the pattern of the freelayer 3 b at a given distance from the pattern 29 e or 29 f. However,the upper surface of the insulation layer 11 may be equal in height tothe upper surface of the pattern of the free layer 3 b or higher thanthe upper surface of the pattern of the free layer 3 b. Furthermore, thepattern of the vertical bias layer 2 b may be spaced apart from thepattern of the free layer 3 b and that of the second free layer 19. Inaddition, the fourth non-magnetic layer 18 may be patterned inconjunction with the second free layer 19 and extended further than thepattern of the second free layer 19. Furthermore, the pattern of thesecond non-magnetic layer 9 may be extended further than that of thefree layer 3 b.

FIGS. 88-90 are fragmentary sectional views illustrating the structureof a magneto-resistance effect element according to a variation of thisembodiment. FIG. 88 shows that fourth magnetic layer 18 is notpatterned.

In addition, FIG. 89 shows that the upper surface of the insulationlayer 11 is higher than that of the pattern of the free layer 3 b.

Furthermore, FIG. 90 shows that the pattern of the vertical bias layer 2b is spaced apart from that of the free layer 3 b and the second freelayer 19. The magneto-resistance effect element shown in FIGS. 88-90 canalso be employed for the magneto-resistance effect head.

Now, a twelfth embodiment according to the present invention isdescribed below. FIGS. 91-94 are fragmentary sectional viewsillustrating the structure of a magneto-resistance effect head accordingto this embodiment.

First, a layered body as shown in FIG. 6 is formed through the steps,shown in FIGS. 4-6, according to the aforementioned first embodiment.

Then, as shown in FIG. 91, on the lower conductive layer 1 and thevertical bias layer 2 b, layered in sequence are a second underlyinglayer for magnetic layer 12 a, a second magnetic layer 12 b, the thirdnon-magnetic layer 13, the second magnetic layer 8, the secondnon-magnetic layer 9, the free layer 3 b, the first non-magnetic layer4, the fixed layer 5, the fixing layer 6 b, and the upper layer 7.

Then, as shown in FIG. 92, a photoresist 21 is formed at the centralportion of the region where no recessed portion 1 a of the lowerconductive layer 1 is formed on the upper layer 7.

Then, as shown in FIG. 93, the second non-magnetic layer 9, the freelayer 3 b, the first non-magnetic layer 4, the fixed layer 5, the fixinglayer 6 b, and the upper layer 7 are etched by dry etching or likemeans. Then, the portion removed by the etching is buried in theinsulation layer 11 and thus a magneto-resistance effect element 39 b isformed.

Then, as shown in FIG. 94, the photoresist 21 is removed, and the upperconductive layer 15 is deposited to form a photoresist (not shown). Withthis photoresist being employed as a mask, the upper conductive layer 15is patterned by dry etching or like means. Thereafter, this photoresistis removed and the upper shield layer 17 is formed thereupon, thusforming a magneto-resistance effect head 69 b.

Now, the structure of the magneto-resistance effect head 69 b accordingto this embodiment is described below. As shown in FIG. 94, themagneto-resistance effect head 69 b is provided with the lower shieldlayer 16, while the lower conductive layer 1 is provided on the lowershield layer 16. The recessed portion 1 a is provided on the uppersurface of the lower conductive layer 1, and the underlying layer forvertical bias layer 2 a and the vertical bias layer 2 b are provided soas to be in the recessed portion 1 a. On the lower conductive layer andthe vertical bias layer 2 b, provided are the second underlying layerfor magnetic layer 12 a, the second magnetic layer 12 b, the thirdnon-magnetic layer 13, and the first magnetic layer 8 b. A pattern madeup of the second non-magnetic layer 9, the free layer 3 b, thenon-magnetic layer 4, the fixed layer 5, the fixing layer 6 b, and theupper layer 7 is formed immediately above the portion surrounded by thepattern of the two vertical bias layers on the magnetic layer 8 b.

In this embodiment, it has been shown in which the second non-magneticlayer 9 is patterned in conjunction with the free layer 3 b, thenon-magnetic layer 4, the fixed layer 5, the fixing layer 6 b, and theupper layer 7. However, the second non-magnetic layer 9 may be extendedlike the pattern of the magnetic layer 8. Alternatively, the secondnon-magnetic layer 9 may be extended further than the free layer 3 b,the non-magnetic layer 4, the fixed layer 5, the fixing layer 6 b, andthe upper layer 7, or may be smaller than the pattern of the magneticlayer 8.

In addition, the underlying layer for vertical bias layer 2 a, thesecond underlying layer for magnetic layer 12 a, and the upper layer 7can be omitted. A protective layer for protecting the vertical biaslayer can be provided on the upper of the vertical bias layer 2 b.Furthermore, the second underlying layer for magnetic layer 12 a, thesecond magnetic layer 12 b, the third non-magnetic layer 13, and thefirst magnetic layer 8 do not always have to extend as shown in FIG. 94.

FIGS. 95 and FIG. 96 are fragmentary sectional views illustrating thestructure of a magneto-resistance effect element according to avariation of this embodiment. FIG. 95 shows that the end portions of thesecond underlying layer for magnetic layer 12 a, the second magneticlayer 12 b, the third non-magnetic layer 13, and the first magneticlayer 8 b are in contact with that of the pattern of the vertical biaslayer 2 b.

In addition, FIG. 96 shows that the end portion of the second underlyinglayer for magnetic layer 12 a, the second magnetic layer 12 b, the thirdnon-magnetic layer 13, and the first magnetic layer 8 b sit on thepattern of the vertical bias layer 2 b.

In addition, the pattern of the second magnetic layer 12 b may be largerthan that of the third non-magnetic layer 13, and the pattern of thethird non-magnetic layer 13 may be larger than the pattern of themagnetic layer 8 b.

Now, a thirteenth embodiment according to the present invention isdescribed below. FIGS. 97-102 are fragmentary sectional viewsillustrating the structure of a magneto-resistance effect head accordingto this embodiment.

First, as shown in FIG. 97, the lower shield layer 16 and the lowerconductive layer 1 are formed successively on a substrate (not shown).

Then, as shown in FIG. 98, the underlying layer for vertical bias layer2 a and the vertical bias layer 2 b are deposited on the lowerconductive layer 1.

Then, as shown in FIG. 99, layered sequentially are the secondunderlying layer for magnetic layer 12 a, the second magnetic layer 12b, the third non-magnetic layer 13, the magnetic layer 8, the secondnon-magnetic layer 9, the underlying layer for free layer 3 a, the freelayer 3 b, the non-magnetic layer 4, the fixed layer 5, the fixing layer6 b, and the upper layer 7.

Then, as shown in FIG. 100, the photoresist 21 is patterned on the upperlayer 7.

Then, as shown in FIG. 101, with the photoresist 21 being employed as amask, the second non-magnetic layer 9, the free layer 3 b, the firstnon-magnetic layer 4, the fixed layer 5, the fixing layer 6 b and theupper layer 7 are etched by dry etching or like means. Thereafter, theportion removed by the etching is buried in the insulation layer 11 andthus a magneto-resistance effect element 39 c is formed.

Then, as shown in FIG. 102, the photoresist 20 is removed, and the upperconductive layer 15 is deposited on the insulation layer 11 and theupper layer 7 to form a photoresist (not shown). With this photoresistbeing employed as a mask, the upper conductive layer 15 is patterned bydry etching or like means. Then, this photoresist is removed and theupper shield layer 17 is formed on the upper conductive layer 15, thusforming a magneto-resistance effect head 69 c.

Now, the structure of the magneto-resistance effect head 69 c accordingto this embodiment is described below. As shown in FIG. 102, themagneto-resistance effect head 69 c has the lower conductive layer 1provided on the lower shield layer 16. The underlying layer for verticalbias layer 2 a and the vertical bias layer 2 b are provided thereupon.Further formed thereupon are the second underlying layer for magneticlayer 12 a, the second magnetic layer 12 b, the third non-magnetic layer13, and the magnetic layer 8 b. On the magnetic layer 8 b, provided arethe second non-magnetic layer 9, the free layer 3 b, the non-magneticlayer 4, the fixed layer 5, the fixing layer 6 b, and the upper layer 7,which have been patterned and buried in the insulation layer 11. Inaddition, the upper conductive layer 15 is provided on the upper layer 7and the insulation layer 11, upon which provided is the upper shieldlayer.

In this embodiment, it has been shown in which the second underlyinglayer for magnetic layer 12 a, the second magnetic layer 12 b, the thirdnon-magnetic layer 13, and the first magnetic layer 8 are patterned.However, the second non-magnetic layer 9 may extend like the pattern ofthe first magnetic layer 8. Alternatively, the second non-magnetic layer9 may be extended further than the pattern of the free layer 3 b, thenon-magnetic layer 4, the fixed layer 5, the fixing layer 6 b, and theupper layer 7 and may be smaller than the pattern of the magnetic layer8.

In addition, the vertical bias film underlying layer 2 a, the secondnon-Underlying layer for magnetic layer 12 a, and the upper layer 7 canbe omitted. Furthermore, a protective layer for protecting the verticalbias layer can be provided above the vertical bias layer 2 b.Furthermore, the second underlying layer for magnetic layer 12 a, thesecond magnetic layer 12 b, the third non-magnetic layer 13, and thefirst magnetic layer 8 do not always have to extend.

FIGS. 103 and 104 are fragmentary sectional views illustrating thestructure of a magneto-resistance effect element according to avariation of this embodiment. FIG. 103 shows that the second underlyinglayer for magnetic layer 12 a, the second magnetic layer 12 b, the thirdnon-magnetic layer 13, and the first magnetic layer 8 b are patterned.

In addition, FIG. 104 shows that the second underlying layer formagnetic layer 12 a, the second magnetic layer 12 b, the thirdnon-magnetic layer 13, and the first magnetic layer 8 are patterned tobe generally equal in size to the pattern of the second non-magneticlayer 9, the free layer 3 b, the first the non-magnetic layer 4, thefixed layer 5, the fixing layer 6 b, and the upper layer 7. Themagneto-resistance effect element shown in FIGS. 103 and 104 can also beemployed for the magneto-resistance effect head.

Furthermore, the pattern of the second magnetic layer 12 b may be largerthan that of the third non-magnetic layer 13, and the pattern of thethird non-magnetic layer 13 may be larger than that of the firstmagnetic layer 8 b.

Now, shown below is an application embodiment of the magneto-resistanceeffect element according to the present invention to a read/write headand a read/write system. FIG. 105 shows a schematic view illustrating amagnetic read/write head according to this embodiment. In this magneticread/write head (a read/write element portion 130), provided on asubstrate 42 is a read head 45, including the aforementionedmagneto-resistance effect head as part thereof, for reading a signalfrom a storage medium. In addition, on the read head 45, there isprovided a write head 46, comprising a magnetic pole 43, a plurality ofcoils 41, and an upper magnetic pole 44, for writing a signal onto thestorage medium. In this case, the magnetic pole 43 may be commonly usedas the upper shield layer or may be provided separately. As shown inFIG. 105, the magneto-sensitive portion of the read head 45 and themagnetic gap of the write head are formed to overlap each other on thesame slider, thereby making it possible to simultaneously position themon the same track. And, the write head 46 applies a magnetic field to astorage medium (not shown) to write data thereon, and the read head 45reads data stored in this storage medium. This read/write head ismachined into a slider to be mounted on a magnetic read/write device.

FIG. 106 is a schematic view illustrating the structure of amagneto-resistance transducer system, comprising the magnetic read/writehead shown in FIG. 105, according to this embodiment. Thismagneto-resistance transducer system is provided with the read/writeelement portion 130 (a magnetic read/write head) formed in a board 129constituting the slider and is protected by a protective film 132. Forexample, the board 129 is formed of Al2O3-TiC composite ceramic or thelike, while the protective film 132 is formed of diamond-like carbon.

The read/write element portion 130 is provided with electrode terminals131 a connected to the write element portion (the write head) andelectrode terminals 131 b connected to the read element portion (theread head). The electrode terminal 131 a applies a drive electriccurrent to the write element portion and is connected to an electriccurrent drive circuit 133 for causing write operation to occur. Inaddition, the electrode terminal 131 b is connected to an electriccurrent generator circuit 134 for conducting a sense current through theread element portion. The electrode terminal 131 b is also connected toa data read circuit 135 for detecting a voltage change caused by achange in specific resistance of the read element portion as a functionof an applied magnetic field to read data information stored on thestorage medium. As described above, the magneto-resistance transducersystem comprises the read/write element portion 130, the electriccurrent generator circuit 134, and the data read circuit 135.

FIG. 107 is a schematic view illustrating an embodiment of a magneticstorage system employing the magneto-resistance transducer system shownin FIG. 106. This magnetic storage system comprises a magneto-resistancetransducer system having a magnetic read/write head 103, sense currentdetecting means 107, and a controller 108. The magnetic storage systemalso comprises a magnetic storage medium 102 having a plurality oftracks for storing data, a first actuator 106 having a VCM (Voice CoilMotor) for moving the magnetic read/write head 103 to a given positionon the magnetic storage medium 102, and a second actuator 101 having amotor for rotating the magnetic storage medium 102. In addition, themagnetic read/write head 103 is supported by a suspension 104 and an arm105.

FIG. 108 is a perspective view illustrating a specific embodiment of themagnetic storage system. In this embodiment, a read head 51 and a writehead 50 are formed on a board 52 that also serves as a head slider andpositioned on a storage medium 53 for read operation. The storage medium53 rotates and the head slider moves relatively thereto 0.2 μm or lessabove the storage medium 53 or in contact therewith. This mechanismallows the read head 51 to be set to where the read head 51 can read amagnetic signal stored on the storage medium 53 from a leak magneticfield 54.

As the magnetic memory system of the present invention, it is possibleto employ hard disk devices, flexible disk devices, and magnetic tapeunits. The hard disk devices include a fixed disk device that allows nodisks to be replaced and a disk device that allows disks to be replaced.

Now, described below is a prototype of a magnetic memory devicefabricated according to the present invention. The magnetic memorydevice comprises three magnetic disks (magnetic storage media) on thebase and houses, on the reverse side of the base, a head drive circuit,a signal processing circuit, and an input/output interface. The magneticmemory device is connected to the outside by a 32-bit bus line. Themagnetic memory device is provided with six heads arranged on both sidesof a magnetic disk, a rotary actuator for driving the heads (actuatormeans), and a drive circuit, a control circuit, and a motor directlyconnected to the disk rotating for use therewith. The disk is 63 mm indiameter and uses the range from 10 mm to 57 mm in diameter as the datastorage surface. A buried servo scheme is employed and thereby no servosurface is prevent, thus making it possible to provide a high density.It is possible to directly connect this device to a small computer as anauxiliary memory device. The input/output interface is provided with acash memory, corresponding to a bus line having transfer speeds withinthe range of 5 to 20 MB per second. It is also possible to provide anexternal controller having a plurality of the devices connected thereto,thereby constituting a large-capacity magnetic disk unit.

Now, the effect of the embodiments according to the present invention isspecifically described below in comparison with comparative examplesthat depart from the scope of the claims. First, for comparisonpurposes, the head having the structure of FIGS. 1 and 2 described inthe section of the prior art was prepared. After the deposition of thefilms, heat treatment was performed for five hours at a temperature of250° C. while a magnetic field of 7.9×10⁵ A/m was being applied in thedirection perpendicular to the magnetic field applied upon deposition.

The following materials were employed as each component that forms thehead. The composition of each of the material shown below is that of thetargets employed for sputtering (atom %), and the numerals in theparentheses denote the thickness of the layer.

Substrate: alumina of 3 μm layered on an altic layer 1.2 mm in thickness

Lower shield layer:Co89Zr4Ta4Cr3 (1 μm)

Lower conductive layer: Ta (20 μm)

Upper electrode layer: not available

Upper shield layer: Co65Ni12Fe23 (1 μm)

Insulation layer: alumina (20 nm)

Underlying layer vertical bias: Cr (10 nm)

Vertical bias: Co74.5Cr10.5Pt15 (33 nm)

Lower gap layer: not available

Upper gap layer: not available

Upper layer: Ta (5 nm)

Underlying layer for free layer: Ta (3 nm)

Fixing layer: Pt46Mn54 (20 nm)

Fixed layer: three-layer film (Co90Fe10 (3 nm)/Ru (0.7 nm)/Co50Fe50 (3nm))

Non-magnetic layer: Al oxide (0.7 nm)

Free layer: Ni82Fe18 (5 nm)

Upper layer: Ta (3 nm)

This head was machined and sliced into a merged read/write head like theread head 45 shown in FIG. 105 and then data was written onto and readfrom a CoCrTa-based medium. And, the write track was 0.7 μm in width andthe read track was 0.4 μm in width.

The TMR element portion was fabricated through the photoresist processemploying the i-line and the milling process. Upon preparing the coilportion of the write head, the photoresist was held at a temperature of250° C. for two hours and thereby hardened.

This process caused the fixed layer and the fixing layer to rotate theirorientation of magnetization which should be directed along the heightof the element, thereby resulting in improper operation of themagneto-resistance effect element. Accordingly, after the read headportion and the write head portion were prepared, magnetization heattreatment was performed for one hour at a temperature 200° C. in amagnetic field of 4.0×10⁴ A/m. Almost no rotation of the magnetizationeasy axis of the free layer in the orientation of magnetization causedby this magnetization heat treatment was observed in the magnetizationcurve.

It was assumed that the coercive force of the medium was 2.4×10⁵ A/m,and MrT (the product of residual magnetization and film thickness) was0.35 emu/cm². Using ten prototype heads of each structure, the readoutput, S/N ratio, and effective track width were measured. The resultsof measurement made on the structure of FIG. 2 are shown in Table 1, andthe results of measurement made on the structure of FIG. 1 are shown inTable 2.

TABLE 1 Element No. Output (mV) (S/N) ratio (dB) 1 3.1 21 2 3.0 20 3 2.819 4 2.9 18 5 2.9 19 6 3.1 21 7 2.9 19 8 3.1 19 9 3.0 21 10 2.8 19

TABLE 2 Element No. Output (mV) (S/N) ratio (dB) 1 1.2 17 2 1.1 16 3 0 04 0.5 12 5 0.2 5 6 0.3 8 7 0.4 9 8 0.2 2 9 0 0 10 0.3 8

The structure of FIG. 1 provides a read output as high as 2.8 to 3.1 mVbut S/N ratio as low as 18 to 21 dB. This was caused by Barkhausen noiseincluded in the read signal. It was found by measuring the R-H loop ofthe head that the hysteresis produced by the inversion of the free layermagnetization was so high as to cause the Barkhausen noise involved inthe magnetic wall displacement of the free layer. In the structure ofFIG. 1, it is considered that since the vertical bias layer and the freelayer are isolated by the insulation layer, the vertical bias magneticfield is not applied sufficiently to the free layer, so that thevertical bias magnetic field does not contribute to the reduction inBarkhausen noise.

On the other hand, in the structure of FIG. 2, the read output was aslow as 0 to 1.2 mV, and accordingly the (S/N) ratio was as low as 0 to17 dB. This is because the sense current leaks out to the vertical biaslayer 2 b and thus does not conduct through the non-magnetic layer 4. Inthis structure, it may be possible in principle to prevent the leakageof the sense current to the vertical bias layer 2 b; however, theleakage cannot be prevented. This is conceivably because the structurecannot be precisely fabricated to prevent the leakage of the sensecurrent to the vertical bias layer 2 b and conduct the sense currentsufficiently through the non-magnetic layer 4. This results from thefact that the vertical bias layer 2 b is in close proximity to the endportion of the non-magnetic layer 4 (barrier layer) in the layered bodymade up of the fixed layer 5, the non-magnetic layer 4, and the freelayer 3.

Then, as an embodiment of the present invention, fabricated was themagneto-resistance effect head of the structure shown in FIGS. 10, 21,31, 37, 49, and 64. And, the following materials were employed as eachcomponent that forms the magneto-resistance effect head.

Substrate: alumina of 3 μm layered on an altic layer 1.2 mm in thickness

Lower shield layer:Co89Zr4Ta4Cr3 (1 μm)

Lower conductive layer: Ta (20 μm)

Upper electrode layer: not available

Upper shield layer: Co65Ni12Fe23 (1 μm)

Insulation layer: alumina (20 nm)

Underlying layer for vertical bias layer: Cr (10 nm)

Vertical bias: Co74.5Cr10.5Pt15 (33 nm)

Lower gap layer: not available

Upper gap layer: not available

Upper layer: Ta (5 nm)

Underlying layer for free layer: Ta (3 nm)

Underlying layer for magnetic layer: Ta (3 nm)

Fixing layer: Pt46Mn54 (20 nm)

Second fixing layer: Pt46Mn54 (20 nm)

Fixed layer: three-layer film (Co90Fe10 (3 nm)/Ru (0.7 nm)/Co50Fe50 (3nm))

Second fixed layer: three-layer film (Co90Fe10 (3 nm)/Ru (0.7nm)/Co50Fe50 (3 nm))

First non-magnetic layer: Al oxide (0.7 nm)

Second non-magnetic layer: Ru (0.75 nm)

Third non-magnetic layer: Ru (0.75 nm)

Fourth non-magnetic layer: Ru (0.75 nm)

Fifth non-magnetic layer: Al oxide (0.7 nm)

Free layer: Ni82Fe18 (5 nm)

Magnetic layer: Ni82Fe18 (5 nm)

Upper layer: Ta (3 nm)

This head was machined and sliced into a merged read/write head like theread head 45 shown in FIG. 105 and then data was written onto and readfrom a CoCrTa-based medium. And, the write track was 0.7 μm in width andthe read track was 0.4 μm in width.

The TMR element portion was fabricated through the photoresist processemploying the i-line and the milling process. Upon preparing the coilportion of the write head, the photoresist was held at a temperature of250° C. for two hours and thereby hardened.

This process caused the fixed layer and the fixing layer to rotate theirorientation of magnetization, which should be directed along the heightof the element, thereby resulting in improper operation of themagneto-resistance effect element. Accordingly, after the read headportion and the write head portion were prepared, magnetization heattreatment was performed for one hour at a temperature 200° C. in amagnetic field of 4.0×10⁴ A/m. Almost no rotation of the magnetizationeasy axis of the free layer in the orientation of magnetization causedby this magnetization heat treatment was observed in the magnetizationcurve.

It was assumed that the coercive force of the medium was 2.4×10⁵ A/m,and MrT (the product of residual magnetization and film thickness) was0.35 emu/cm². Using ten prototype heads of each structure, the readoutput, S/N ratio, and effective track width were measured. The resultsof measurement made on the structure of FIGS. 10, 21, 31, 37, 49, and 64are shown in Tables 1 to 8.

TABLE 3 Element Output (S/N) ratio Effective track No. (mV) (dB) width(μm) 1 3.0 27 0.61 2 3.1 26 0.59 3 2.9 27 0.60 4 3.0 28 0.61 5 2.8 260.57 6 3.0 27 0.57 7 3.1 28 0.60 8 3.0 27 0.59 9 2.8 26 0.58 10 2.8 250.57

TABLE 4 Element Output (S/N) ratio Effective track No. (mV) (dB) width(μm) 1 3.0 27 0.58 2 2.8 28 0.59 3 2.9 27 0.57 4 2.8 27 0.57 5 2.7 260.59 6 3.0 25 0.60 7 3.1 27 0.59 8 3.0 28 0.58 9 3.1 26 0.57 10 3.0 250.60

TABLE 5 Element Output (S/N) ratio Effective track No. (mV) (dB) width(μm) 1 3.2 27 0.58 2 3.1 27 0.57 3 2.9 28 0.56 4 2.7 26 0.58 5 2.8 270.60 6 2.9 27 0.60 7 2.8 26 0.58 8 3.0 27 0.57 9 3.0 28 0.59 10 3.1 270.60

TABLE 6 Element Output (S/N) ratio Effective track No. (mV) (dB) width(μm) 1 2.9 28 0.58 2 2.8 27 0.59 3 2.7 26 0.56 4 2.8 27 0.58 5 2.9 270.56 6 2.9 26 0.55 7 2.7 27 0.54 8 2.8 26 0.58 9 2.7 26 0.56 10 2.9 280.57

TABLE 7 Element Output (S/N) ratio Effective track No. (mV) (dB) width(μm) 1 2.8 27 0.55 2 2.7 28 0.54 3 2.8 26 0.53 4 2.9 27 0.54 5 2.9 280.54 6 3.0 27 0.542 7 2.8 26 0.53 8 2.9 27 0.54 9 2.9 28 0.55 10 2.8 250.51

TABLE 8 Element Output (S/N) ratio Effective track No. (mV) (dB) width(μm) 1 2.9 25 4.8 2 2.9 26 4.9 3 2.7 26 4.8 4 2.6 27 5.1 5 2.7 26 4.8 62.8 26 5.0 7 2.5 25 5.1 8 2.5 27 4.9 9 2.6 25 4.6 10 2.6 25 4.5

It can be seen that any one of the structures shown in FIGS. 10, 21, 31,37, 49 and 64 provides a S/N ratio of 25 dB or more, thus providing asignificantly improved S/N ratio in comparison with the prior-artexample. This is because any one of the structures can prevent the sensecurrent from bypassing the barrier layer, and therefore providesufficient output and successfully apply a proper amount of verticalbias magnetic field to the free layer, thereby making it possible tosufficiently reduce noise and thus provide a good S/N ratio. Among themagneto-resistance effect heads shown in FIGS. 10, 21, 31, 37, 49, and64, the one shown in FIG. 64 has the smallest effective track width andprovides the best result. This is conceivably because themagneto-resistance effect head shown in FIG. 64 has a layeredanti-ferromagnetic layer structure of the magnetic layer 8, the thirdnon-magnetic layer 13, and the second magnetic layer 12. This structureis thereby prevented from being subjected to the effect of the leakagemagnetic field from the medium, so that the read effective track widthis determined only by the width of the free layer 3 b.

1. A magneto-resistance effect element comprising: a lower conductivelayer; a first fixed layer provided on the lower conductive layer andhaving a pinned orientation of magnetization; a first non-magnetic layerprovided on the first fixed layer; a first free layer provided on thefirst non-magnetic layer and having an orientation of magnetizationvaried by a magnetic field applied thereto, the first fixed layer, thefirst non-magnetic layer and the first free layer being etched to form afirst vertical pattern; a first insulation layer formed about the firstvertical pattern so as to bury the first vertical pattern therein, thefirst insulation layer having a height equal to the first verticalpattern near the first vertical pattern but slightly lower than thefirst vertical pattern at a given distance from the first verticalpattern; a magnetic layer provided on the first free layer andmagnetically coupled to the first free layer; a second free layerprovided on the magnetic layer and magnetically coupled to the magneticlayer; a second non-magnetic layer provided on the second free layer; asecond fixed layer provided on the second non-magnetic layer and havinga pinned orientation of magnetization, the second free layer, the secondnon-magnetic layer and the second fixed layer being etched to form asecond vertical pattern aligned with the first vertical pattern; avertical bias layer provided on the first insulation layer for applyinga magnetic field to said magnetic layer, and a sense current fordetecting a change in electrical resistance of said first and secondnon-magnetic layers flows substantially in perpendicular relation tosaid first and second non-magnetic layers; and a second insulation layerformed over the vertical bias layer and about the second verticalpattern so as to bury the second vertical pattern theren.
 2. Themagneto-resistance effect element according to claim 1, wherein saidmagnetic layer is equal to or greater than said first and second freelayers in length in the direction of the magnetic field applied by saidvertical bias layer.
 3. The magneto-resistance effect element accordingto claim 1, further comprising a first fixing layer, disposed below saidfirst fixed layer, for pinning the orientation of magnetization of saidfirst fixed layer.
 4. The magneto-resistance effect element according toclaim 1, further comprising a second fixing layer, disposed above saidsecond fixed layer, for pinning the orientation of magnetization of saidsecond fixed layer.
 5. The magneto-resistance effect element accordingto claim 1, wherein said first free layer is magnetically coupled tosaid magnetic layer by anti-ferromagnetic coupling or ferromagneticcoupling.
 6. The magneto-resistance effect element according to claim 1,wherein said magnetic layer is magnetically coupled to said second freelayer by anti-ferromagnetic coupling or ferromagnetic coupling.
 7. Themagneto-resistance effect element according to claim 1, wherein at leastpart of said magnetic layer is in direct contact with said vertical biaslayer.